Filed Pursuant to Rule 424(b)(7)

Registration No. 333-175226

The information in this prospectus supplement is not complete and may be changed. This prospectus supplement and the accompanying prospectus are not an offer to sell these securities and it is not soliciting an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

Subject to Completion, dated May 2, 2016

Prospectus Supplement
To the prospectus dated March 28, 2012

7,300,047 Shares of Common Stock

All of the shares of common stock of United Community Banks, Inc., which we refer to in this prospectus supplement as “United,” are being sold by the selling shareholder identified in this prospectus supplement. United will not receive any of the proceeds from the sale of the shares being sold by the selling shareholder. 

The common stock of United is listed on the Nasdaq Global Select Market under the ticker symbol “UCBI.” The last reported sale of the common stock on April 29, 2016 was $20.13 per share. 

Investing in our common stock involves a high degree of risk. See the section entitled “Risk Factors” beginning on page S-4 of this prospectus supplement to read about factors you should consider before buying shares of our common stock.

The underwriter has agreed to purchase the common stock from the selling shareholder at a price of $ per share, which will result in aggregate proceeds of $ to the selling shareholder. The underwriter may offer the shares of common stock from time to time for sale in one or more transactions on the Nasdaq Global Select Market, in the over-the-counter market, through negotiated transactions or otherwise at market prices prevailing at the time of sale or at negotiated prices. See “Underwriting.”

Neither the U.S. Securities and Exchange Commission, or the “SEC,” nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus supplement. Any representation to the contrary is a criminal offense. An investment in the securities of United Community Banks, Inc. is not insured by the Federal Deposit Insurance Corporation or any other government agency.

The underwriter expects to deliver the shares to purchasers on or about May      , 2016.

 J.P. Morgan

Prospectus Supplement dated May  , 2016.

TABLE OF CONTENTS

Prospectus Supplement 

Prospectus 

Neither we, the selling shareholder, nor the underwriter have authorized anyone to provide you with different information or to make any representations other than those contained or incorporated by reference into this prospectus supplement, the accompanying prospectus or in any free writing prospectus we have prepared. If anyone provides you with different or inconsistent information, you should not rely on it. This prospectus supplement and the accompanying prospectus do not constitute an offer to sell, or a solicitation of an offer to purchase, the securities offered by this prospectus supplement and the accompanying prospectus in any jurisdiction in which it is unlawful to make such offer or solicitation.

You should not assume that the information contained in this prospectus supplement, the accompanying prospectus and the documents incorporated by reference herein and therein is accurate as of any date other than the date on the front cover of those documents. Our business, financial condition, results of operations and prospects may have changed since that date.

For investors outside the United States: Neither we, the selling shareholder nor the underwriter have done anything that would permit this offering or possession or distribution of this prospectus supplement and the accompanying prospectus in any jurisdiction where action for that purpose is required, other than in the United States. You are required to inform yourselves about and to observe any restrictions relating to this offering and the distribution of this prospectus supplement and the accompanying prospectus outside of the United States.

ABOUT THIS PROSPECTUS SUPPLEMENT

This document has two parts, a prospectus supplement and an accompanying prospectus dated March 28, 2012. This prospectus supplement and the accompanying prospectus are part of a registration statement on Form S-3 that we filed with the SEC utilizing a “shelf” registration process. Under this shelf registration process, the selling shareholder named in a prospectus supplement may, from time to time, offer and sell our common stock in one or more offerings or resales.

The accompanying prospectus provides you with a general description of our common stock, which the selling shareholder may offer pursuant to this prospectus supplement. This prospectus supplement, which describes certain matters relating to us and the specific terms of this offering of shares of our common stock, adds to and updates information contained in the accompanying prospectus and the documents incorporated by reference herein. Any statement that we make in the accompanying prospectus will be deemed modified or superseded by any inconsistent statement made by us in this prospectus supplement.

The rules of the SEC allow us to incorporate by reference information into this prospectus supplement. This information incorporated by reference is considered to be a part of this prospectus supplement, and information that we file later with the SEC, to the extent incorporated by reference, will automatically update and supersede this information. See “Incorporation of Certain Information by Reference.” You should read both this prospectus supplement and the accompanying prospectus together with the additional information incorporated by reference herein and therein, including all documents described under the headings “Incorporation of Certain Information by Reference” and “Where You Can Find More Information” in this prospectus supplement before investing in our common stock.

As used in this prospectus supplement and the accompanying prospectus, unless the context requires otherwise, the terms “we,” “us,” “our,” “United” or “the Company” refer to United Community Banks, Inc. and its subsidiaries on a consolidated basis.

RISK FACTORS

Investing in our common stock involves a high degree of risk. You should carefully review the risks and uncertainties listed below, together with the risk factors described in the sections entitled “Risk Factors” in the accompanying prospectus and in our most recent Annual Report on Form 10-K, as updated by any subsequent Quarterly Reports on Form 10-Q or Current Reports on Form 8-K that we have filed or will file with the SEC and that are incorporated by reference into this prospectus supplement. The risks described in these documents are not the only ones we face, but those that we currently consider to be material. There may be other unknown or unpredictable economic, business, competitive, regulatory or other factors that could have material adverse effects on our future results. Past financial performance may not be a reliable indicator of future performance, and historical trends should not be used to anticipate results or trends in future periods. Please also read carefully the section below entitled “A Warning About Forward-Looking Statements.”

Risks Related to the Ownership of the Common Stock

We may issue additional securities that could result in dilution of your investment.

Our Board of Directors may determine from time to time that there is a need to obtain additional capital through the issuance of additional shares of the common stock or other securities. These issuances would likely dilute the ownership interests of our investors and may dilute the per share book value of the common stock.

Our common stock is equity and therefore is subordinate to our and our subsidiaries’ indebtedness and our preferred stock.

Our common stock is an equity interest and does not constitute indebtedness of United. Consequently, our common stock ranks junior to all current and future indebtedness of United and other non-equity claims against us with respect to assets available to satisfy claims against us, including in the event of our liquidation or dissolution. We may, and the Bank and our other subsidiaries may also, incur additional indebtedness from time to time and may increase our aggregate level of outstanding indebtedness.

Further, holders of our common stock are subject to the prior dividend and liquidation rights of any holders of our preferred stock that may be outstanding from time to time. Our Board of Directors is authorized to cause us to issue additional classes or series of preferred stock without any action on the part of our shareholders. If we issue preferred shares in the future that have a preference over our common stock with respect to the payment of dividends or distributions upon liquidation, or if we issue preferred shares with voting rights that dilute the voting power of our common stock, then the rights of holders of our common stock could be adversely affected. Further, the market price of our common stock could be adversely affected.

We rely on dividends we receive from our subsidiary and are subject to restrictions on our ability to declare or pay dividends.

As a bank holding company, our ability to pay dividends depends primarily on the receipt of dividends from our wholly-owned bank subsidiary, the Bank. Dividend payments from the Bank are subject to legal and regulatory limitations, generally based on retained earnings, imposed by bank regulatory agencies. The ability of the Bank to pay dividends is also subject to financial condition, regulatory capital requirements, capital expenditures and other cash flow requirements. As of December 31, 2015, pursuant to these restrictions, the Bank did not have the ability to pay dividends to United without prior regulatory approval.

The market price of our common stock may be volatile and could decline after this offering.

Volatility in the market price of our common stock may prevent you from being able to sell your shares at or above the price you paid for your shares. The market price of our common stock may fluctuate significantly. The stock markets have experienced extreme volatility in recent years that has been unrelated to the operating performance of particular companies. These broad market fluctuations may adversely affect the market price of our common stock.

If securities or industry analysts do not publish research (or publish misleading or unfavorable research) about our business, our stock price and trading volume could decline.

The trading market for our common stock depends in part on the research and reports that securities or industry analysts publish about us or our business. If one or more of the analysts that covers our common stock downgrades our stock or publishes misleading or unfavorable research about our business, our stock price would likely decline. If one or more of the analysts ceases coverage of our common stock or fails to publish reports on us regularly, demand for our common stock could decrease, which could cause our common stock price or trading volume to decline.

An entity holding as little as a 5% interest in our outstanding common stock could, under certain circumstances, be subject to regulation as a “bank holding company.”

Any entity, including a “group” composed of natural persons, owning or controlling with the power to vote 25% or more of our outstanding common stock, or 5% or more if the holder otherwise exercises a “controlling influence” over us, may be subject to regulation as a “bank holding company” in accordance with the Bank Holding Company Act of 1956, as amended (the “BHC Act”). In addition, (i) any bank holding company or foreign bank with a U.S. presence may be required to obtain the approval of the Federal Reserve under the BHC Act to acquire or retain 5% or more of our outstanding common stock and (ii) any person not otherwise defined as a company by the BHC Act and its implementing regulations may be required to obtain the approval of the Federal Reserve under the Change of Bank Control Act of 1978, as amended, to acquire or retain 10% or more of our outstanding common stock.

A company that acquires “control” of a bank or a bank holding company will itself become a bank holding company. Although “control” for purposes of the BHC Act generally requires the acquisition of 25% or more of a class of voting shares or the ability to appoint a majority of the board of directors, the Federal Reserve has the authority to determine, after a hearing, that a company has the ability to exercise a controlling influence over a bank or a bank holding company. Becoming a bank holding company imposes statutory and regulatory restrictions and obligations, such as providing managerial and financial strength for any bank subsidiaries. Regulation as a bank holding company could require the holder to divest all or a portion of the holder’s investment in the common stock or those nonbanking investments that may be deemed impermissible or incompatible with bank holding company status, such as a material investment in a company unrelated to banking.

An investment in the common stock is not an insured deposit.

The shares of common stock are not bank deposits and, therefore, are not insured against loss by the Federal Deposit Insurance Corporation (“FDIC”) or any other public or private entity. Investment in the common stock is inherently risky for the reasons described in this “Risk Factors” section and elsewhere in this prospectus supplement and the accompanying prospectus, including any documents incorporated herein by reference, and is subject to the same market forces that affect the capital stock in any company. As a result, if you acquire shares of the common stock, you may lose some or all of your investment.

Risks Associated with Our Business and Related to Regulatory Events

The Dodd-Frank Act, among other things, subjects banks with assets in excess of $10 billion to additional costs.

The Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010 (the “Dodd-Frank Act”) and its implementing regulations subject banks with assets in excess of $10 billion to additional requirements, such as the imposition of higher FDIC premiums, reduced debit card interchange fees, enhanced risk management frameworks and stress testing, all of which increase operating costs and reduce earnings. As we approach $10 billion in assets, we have incurred and will be required to incur further additional costs to address these additional requirements.

For additional risks associated with our business and industry, as well as the risks related to legislative and regulatory events, see the section entitled “Risk Factors” in our Annual Report on Form 10-K for the year ended December 31, 2015, which is incorporated in this prospectus supplement by reference.

A WARNING ABOUT FORWARD-LOOKING STATEMENTS

This prospectus supplement contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), about United and its subsidiaries. These forward-looking statements are intended to be covered by the safe harbor for forward-looking statements provided by the Private Securities Litigation Reform Act of 1995. Forward-looking statements are not statements of historical fact, and can be identified by the use of forward-looking terminology such as “believes,” “expects,” “may,” “will,” “could,” “should,” “projects,” “plans,” “goal,” “targets,” “potential,” “estimates,” “pro forma,” “seeks,” “intends,” or “anticipates,” the negative thereof or comparable terminology. Forward-looking statements include discussions of strategy, financial projections, guidance and estimates (including their underlying assumptions), statements regarding plans, objectives, expectations or consequences of various transactions or events, and statements about the future performance, operations, products and services of United and its subsidiaries. We caution our investors and other readers not to place undue reliance on such statements.

Our businesses and operations are and will be subject to a variety of risks, uncertainties and other factors. Consequently, actual results and experience may materially differ from those contained in any forward-looking statements. Such risks, uncertainties and other factors that could cause actual results and experiences to differ from those projected include, but are not limited to, the risk factors set forth in this prospectus supplement, our Annual Report on Form 10-K for the year ended December 31, 2015, as well as the following factors:

Additional information with respect to factors that may cause actual results to differ materially from those contemplated by such forward-looking statements may also be included in other reports that United files with the SEC. United cautions that the foregoing list of factors is not exclusive, and that you should not place undue reliance on forward-looking statements. United does not intend to update any forward-looking statement, whether written or oral, relating to the matters discussed in this prospectus supplement.

USE OF PROCEEDS

The selling shareholder will receive all of the net proceeds from the sale of shares of our common stock offered by it pursuant to this prospectus supplement and the accompanying prospectus. We will not receive any proceeds from the sale of these shares of our common stock. The selling shareholder will bear any underwriting commissions and discounts and other related costs attributable to its sale of our common stock, and we will bear the remaining expenses as required by the investment agreement between United and the selling shareholder. See “Selling Shareholder.”

PRICE RANGE OF COMMON STOCK

Our common stock is listed on the Nasdaq Global Select Market under the ticker symbol “UCBI.”

On April 29, 2016, the last quoted price per share of our common stock on the Nasdaq Global Select Market was $20.13. As of April 29, 2016, there were approximately 8,200 record holders of our common stock.

The following table sets forth the high and low sales price per share of our common stock as reported on the Nasdaq Global Select Market:

DIVIDEND POLICY

United is a legal entity separate and distinct from the Bank.  Most of the revenue of United results from dividends paid to it by the Bank.  There are statutory and regulatory requirements applicable to the payment of dividends by the Bank, as well as by United to its shareholders.

Under the regulations of the Georgia Department of Banking and Finance (the “DBF”), a state bank with negative retained earnings may declare dividends by first obtaining the written permission of the DBF.  If a state bank has positive retained earnings, it may declare a dividend without DBF approval if it meets all the following requirements:

The payment of dividends by United and the Bank may also be affected or limited by other factors, such as the requirement to maintain adequate capital above regulatory guidelines.  In addition, if, in the opinion of the applicable regulatory authority, a bank under its jurisdiction is engaged in or is about to engage in an unsafe or unsound practice (which, depending upon the financial condition of the bank, could include the payment of dividends), such authority may require, after notice and hearing, that such bank cease and desist from such practice. The FDIC has issued a policy statement providing that insured banks should generally only pay dividends out of current operating earnings. In addition to the formal statutes and regulations, regulatory authorities consider the adequacy of the Bank’s total capital in relation to its assets, deposits and other such items. Capital adequacy considerations could further limit the availability of dividends from the Bank.

Due to our accumulated deficit (negative retained earnings), the Bank must receive pre-approval from the DBF and FDIC to pay cash dividends to United in 2016.  In 2015, 2014 and 2013, the Bank paid a cash dividend of $77.5 million, $129 million and $50.0 million, respectively, to United as timely approved by the DBF and FDIC. United declared cash dividends on its common stock of $0.22 per share in 2015 and $0.11 per share in 2014, but did not declare or pay any dividends in its common stock in 2013.

SELLING SHAREHOLDER

The following table sets forth information as of April 26, 2016 with respect to the ownership of our common stock by the selling shareholder.

DESCRIPTION OF CAPITAL STOCK

The authorized capital stock of United currently consists of 100,000,000 shares of common stock, $1.00 par value per share, 26,000,000 shares of non-voting common stock, $1.00 par value per share, and 10,000,000 shares of preferred stock, $1.00 par value per share.

Common Stock

All voting rights are vested in the holders of the common stock. Each holder of common stock is entitled to one vote per share on any issue requiring a vote at any meeting. The shares do not have cumulative voting rights. Upon liquidation, holders of United’s common stock, together with holders of United’s non-voting common stock, will be entitled to receive on a pro rata basis, after payment or provision for payment of all our debts and liabilities, and after all distributions payments are made to holders of any of United’s preferred stock, all of United’s assets available for distribution, in cash or in kind.

Subject to the rights of any holders of United’s preferred stock to receive dividends, all shares of United’s common stock, together with all shares of United’s non-voting common stock, are entitled to share equally in any dividends that United’s Board of Directors may declare on its common stock and non-voting common stock from sources legally available for distribution.

As of April 26, 2016, 66,277,036 shares of common stock were issued and outstanding, exclusive of 494,131.555 shares issuable to participants in United’s Deferred Compensation Plan and 773,256 shares reserved for issuance upon the exercise of outstanding options and vesting of restricted stock. The outstanding shares of United common stock are duly authorized, validly issued, fully paid, and nonassessable.

Non-Voting Common Stock

United’s authorized non-voting common stock consists of 26,000,000 shares. Except with respect to voting rights and as specifically set forth below, the non-voting common stock has the same designations, powers, preferences, limitations, restrictions, and relative rights as, and is identical in all respects to, United’s common stock.

Except as required by Georgia law or United’s articles of incorporation, holders of the non-voting common stock have no right to vote on any matter submitted to a vote at a meeting of United’s shareholders. United’s articles of incorporation provide that, in addition to any other vote required by law, the affirmative vote of the holders of a majority of the outstanding shares of the non-voting common stock, voting separately as a class, will be required to amend, alter or repeal any provision of the articles of incorporation that significantly and adversely affects the rights, preferences or privileges of the non-voting common stock.

Subject to any preferential dividend rights of any preferred stock of United, the holders of non-voting common stock will be entitled to receive, to the extent permitted by law, such dividends as may be declared from time to time by United’s Board of Directors on the common stock. If a dividend is declared and paid with respect to United’s common stock, then the Board of Directors will declare and pay an equivalent dividend, on a per share basis, to the non-voting common stock. Likewise, if the Board of Directors declares and pays a dividend on the non-voting common stock, it will declare and pay an equivalent dividend, on a per share basis, on the common stock.

After distribution in full of any preferential amount to be distributed to the holders of any preferred stock of United, holders of non-voting common stock and common stock will be entitled to receive, in the event of the voluntary or involuntary liquidation, dissolution, distribution of assets or winding-up of United, all of United’s remaining assets of whatever kind available for distribution to the shareholders ratably in proportion to the number of shares of common stock and non-voting common stock held by them.

The non-voting common stock may be converted into common stock by any holder of non-voting common stock, other than the initial holder of such non-voting common stock or an affiliate thereof, who acquires one or more shares of non-voting common stock in an “Approved Transfer.” An “Approved Transfer” means a sale or other transfer (i) to an affiliate of the holder of the non-voting common stock to be transferred under common control with such holder’s ultimate parent, general partner or investment advisor but only if the transferee agrees in writing for the benefit of United to be bound by the terms of an applicable Investor Agreement; (ii) in a widely distributed public offering registered pursuant to the Securities Act of 1933; (iii) to a person that is acquiring at least a majority of United’s outstanding “voting securities” (as defined in the BHC Act and any rules or regulations promulgated thereunder) not including any voting securities such person is acquiring from the holder of the non-voting common stock to be transferred or its affiliates; or (iv) upon certification by the holder of the non-voting common stock to be transferred in writing to United that such holder believes that the transferee shall not, after giving effect to such transfer, own for purposes of the BHC Act, or the Change of Bank Control Act, and any rules and regulations promulgated thereunder, more than 2% of any class of voting securities of United outstanding at such time.

As of April 26, 2016, 5,285,516 shares of non-voting common stock were issued and outstanding, 4,026,724 shares of which were owned by the selling shareholder. When and if any such shares of non-voting common stock are sold by the selling shareholder, and distributed by the underwriter, in the offering contemplated by this prospectus supplement, each such share will have been converted into a share of common stock.

Preferred Stock

United is authorized to issue 10,000,000 shares of preferred stock, issuable in specified series and having specified voting, dividend, conversion, liquidation, and other rights and preferences as United’s Board of Directors may determine. The preferred stock may be issued for any lawful corporate purpose without further action by United shareholders. The issuance of any preferred stock that has conversion rights might have the effect of diluting the interests of United’s other shareholders. In addition, shares of preferred stock could be issued with certain rights, privileges, and preferences, which would deter a tender or exchange offer or discourage the acquisition of control of United.

Of such authorized number of shares of preferred stock, (i) 1,000,000 shares of junior preferred stock are authorized, with no shares issued and outstanding; (ii) 287,411 shares of Series A preferred stock are authorized, with no shares issued and outstanding; (iii) 180,000 shares of Series B preferred stock are authorized, with no shares issued and outstanding; (iv) 65,000 shares of Series C preferred stock are authorized, with no shares issued and outstanding; (v) 25,000 shares of Series D preferred stock are authorized, with no shares issued and outstanding; (vi) 1,000,000 shares of Series E preferred stock are authorized, with no shares issued and outstanding; (vii) 195,872 shares of Series F preferred stock are authorized, with no shares issued and outstanding; (viii) 151,185 shares of Series G preferred stock are authorized, with no shares issued and outstanding; and (ix) 9,992 shares of Series H preferred stock are authorized, with no shares issued and outstanding.

Trust Preferred Securities

United has two wholly owned statutory trusts, which have issued guaranteed preferred interests in United’s junior subordinated deferrable interest debentures. The debentures represent the sole asset of each of the trusts. These debentures qualify as Tier I capital under Federal Reserve Board guidelines. All of the common securities of the trusts are owned by United. United has entered into contractual arrangements which, taken collectively, fully and unconditionally, guarantee payment of: (1) accrued and unpaid distributions required to be paid on the securities; (2) the redemption price with respect to any securities called for redemption by the respective trust; and (3) payments due upon a voluntary or involuntary dissolution, winding up or liquidation of the respective trust. The following is a description of each trust preferred security.

In September 2006, United acquired Southern Bancorp, Inc. (“SBC”) and its wholly owned Delaware statutory trust, Southern Bancorp Capital Trust I (“SBC Trust”), which issued $4.25 million of floating rate capital securities of SBC Trust and $132,000 in floating rate common securities to SBC. The proceeds from the issuance of the securities were used by SBC Trust to purchase $4.382 million of junior subordinated debentures of SBC that bear interest at a rate, reset quarterly, equal to the prime rate plus 1%. The securities accrue and pay distributions quarterly at the then applicable interest rate. The securities mature on March 31, 2034 unless the maturity date is accelerated pursuant to the indenture after March 31, 2009. United now has the right to redeem the debentures purchased by SBC Trust in whole or in part at any time. As specified in the debenture, if the debentures are redeemed prior to maturity, the redemption price will include any accrued but unpaid interest.

In October 2008, United formed a wholly owned Delaware statutory business trust, United Community Statutory Trust III (“United Statutory Trust III”), which issued $1.238 million of trust preferred securities. The proceeds from the sale of the trust preferred securities were used by United Statutory Trust III to purchase $1.238 million in aggregate principal amount of United’s variable rate junior subordinate debentures, which bear interest at a variable rate equal to prime plus 3%. The securities accrue and pay distributions at a variable rate equal to the prime rate plus 3% per annum of the stated liquidation value of $1,000 per capital security. The securities are mandatorily redeemable upon maturity of the debentures on October 31, 2038, or upon earlier redemption as provided in the indenture. United now has the right to redeem the debentures purchased by United Statutory Trust III in whole or in part at any time.

Transfer Agent and Registrar

The transfer agent and registrar for United’s common stock and the debentures is Continental Stock Transfer & Trust Company.

UNITED STATES FEDERAL INCOME TAX CONSIDERATIONS FOR NON-U.S. HOLDERS

The following is a discussion of material U.S. federal income tax considerations relating to the purchase, ownership and disposition of our common stock by Non-U.S. Holders (as defined below) that purchase our common stock pursuant to this offering and hold such common stock as a capital asset. This discussion is based on the Code, U.S. Treasury regulations promulgated or proposed thereunder, and administrative and judicial interpretations thereof, all as in effect on the date hereof and all of which are subject to change, possibly with retroactive effect, or to different interpretation. This discussion does not address all of the U.S. federal income tax considerations that may be relevant to specific Non-U.S. Holders in light of their particular circumstances or to Non-U.S. Holders subject to special treatment under U.S. federal income tax law (such as banks, insurance companies, dealers in securities or other Non-U.S. Holders that generally mark their securities to market for U.S. federal income tax purposes, foreign governments, international organizations, tax-exempt entities, certain former citizens or residents of the United States, or Non-U.S. Holders that hold our common stock as part of a straddle, hedge, conversion or other integrated transaction). This discussion does not address any U.S. state or local or non-U.S. tax considerations or any U.S. federal gift or alternative minimum tax considerations.

As used in this discussion, the term “Non-U.S. Holder” means a beneficial owner of our common stock that, for U.S. federal income tax purposes, is:

If an entity treated as a partnership for U.S. federal income tax purposes invests in our common stock, the U.S. federal income tax considerations relating to such investment will depend in part upon the status and activities of such entity and the particular partner. Any such entity should consult its own tax advisor regarding the U.S. federal income tax considerations applicable to it and its partners relating to the purchase, ownership and disposition of our common stock.

PERSONS CONSIDERING AN INVESTMENT IN OUR COMMON STOCK SHOULD CONSULT THEIR OWN TAX ADVISORS REGARDING THE U.S. FEDERAL, STATE AND LOCAL AND NON-U.S. INCOME, ESTATE AND OTHER TAX CONSIDERATIONS RELATING TO THE PURCHASE, OWNERSHIP AND DISPOSITION OF OUR COMMON STOCK IN LIGHT OF THEIR PARTICULAR CIRCUMSTANCES.

Distributions on Common Stock

If we make a distribution of cash or other property (other than certain pro rata distributions of our common stock or rights to acquire our common stock) in respect of a share of our common stock, the distribution generally will be treated as a dividend to the extent it is paid from our current or accumulated earnings and profits (as determined under U.S. federal income tax principles). If the amount of such distribution exceeds our current and accumulated earnings and profits, such excess generally will be treated first as a tax-free return of capital to the extent of the Non-U.S. Holder’s adjusted tax basis in such share of our common stock, and then as capital gain (which will be treated in the manner described below under “Sale, Exchange or Other Disposition of Common Stock”). Distributions treated as dividends on our common stock that are paid to or for the account of a Non-U.S. Holder generally will be subject to U.S. federal withholding tax at a rate of 30%, or at a lower rate if provided by an applicable tax treaty and the Non-U.S. Holder provides the documentation (generally, IRS Form W-8BEN or IRS Form W-BEN-E) required to claim benefits under such tax treaty to the applicable withholding agent. Special documentation requirements apply to claim benefits under such a tax treaty when our common stock is held though certain foreign intermediaries or Non-U.S. entities that are pass through entities.

If, however, a dividend is effectively connected with the conduct of a trade or business in the United States by a Non-U.S. Holder (and, if required by an applicable income tax treaty, is attributable to a U.S. permanent establishment), such dividend generally will not be subject to the 30% U.S. federal withholding tax if such Non-U.S. Holder provides the appropriate documentation (generally, IRS Form W-8ECI) to the applicable withholding agent. Instead, such Non-U.S. Holder generally will be subject to U.S. federal income tax on such dividend in substantially the same manner as a U.S. person (except as provided by an applicable tax treaty). In addition, a Non- U.S. Holder that is treated as a corporation for U.S. federal income tax purposes may be subject to a branch profits tax at a rate of 30% (or a lower rate if provided by an applicable tax treaty) on its effectively connected income for the taxable year, subject to certain adjustments.

The foregoing discussion is subject to the discussion below under “—FATCA Withholding” and “—Information Reporting and Backup Withholding.”

Sale, Exchange or Other Disposition of Common Stock

A Non-U.S. Holder generally will not be subject to U.S. federal income tax on any gain recognized on the sale, exchange or other disposition of our common stock unless:

Generally, a corporation is a “United States real property holding corporation” if the fair market value of its United States real property interests equals or exceeds 50% of the sum of the fair market value of its worldwide real property interests and its other assets used or held for use in a trade or business (all as determined for U.S. federal income tax purposes). We believe that we presently are not, that we have not been at any time during the five-year period ending as of the date of this offering and we do not presently anticipate that we will become, a United States real property holding corporation.

The foregoing discussion is subject to the discussion below under “—FATCA Withholding” and “—Information Reporting and Backup Withholding.”

FATCA Withholding

Under the Foreign Account Tax Compliance Act provisions of the Code and related U.S. Treasury guidance, or “FATCA,” a withholding tax of 30% will be imposed in certain circumstances on payments of (i) dividends on our common stock and (ii) on or after January 1, 2019, gross proceeds from the sale or other disposition of our common stock. In the case of payments made to a “foreign financial institution” (such as a bank, a broker or an investment fund), as a beneficial owner or as an intermediary, this tax generally will be imposed, subject to certain exceptions, unless such institution (i) has agreed to (and does) comply with the requirements of an agreement with the United States, or an “FFI Agreement,” or (ii) is required to (and does) comply with FATCA pursuant to applicable foreign law enacted in connection with an intergovernmental agreement between the United States and a foreign jurisdiction, or an “IGA,” in either case to, among other things, collect and provide to the U.S. tax authorities or other relevant tax authorities certain information regarding U.S. account holders of such institution, and, in either case such institution provides the withholding agent with a certification as to its FATCA status. In the case of payments made to a foreign entity that is not a financial institution (as a beneficial owner), the tax generally will be imposed, subject to certain exceptions, unless such entity provides the withholding agent with a certification as to its FATCA status and in certain cases, identifies any “substantial” U.S. owner (generally, any specified U.S. person that directly or indirectly owns more than a specified percentage of such entity). If our common stock is held through a foreign financial institution that has agreed to comply with the requirements of an FFI Agreement or is subject to similar requirements under applicable foreign law enacted in connection with an IGA, such foreign financial institution (or, in certain cases, a person paying amounts to such foreign financial institution) generally will be required, subject to certain exceptions, to withhold tax on payments of dividends and proceeds described above made to (i) a person (including an individual) that fails to provide any required information or documentation or (ii) a foreign financial institution that has not agreed to comply with the requirements of an FFI Agreement, unless such foreign financial institution is required to (and does) comply with FATCA pursuant to applicable foreign law enacted in connection with an IGA. Each Non-U.S. Holder should consult its own tax advisor regarding the application of FATCA to the ownership and disposition of our common stock.

Information Reporting and Backup Withholding

Amounts treated as payments of dividends on our common stock paid to a Non-U.S. Holder and the amount of any U.S. federal tax withheld from such payments generally must be reported annually to the IRS and to such Non-U.S. Holder by the applicable withholding agent.

The information reporting and backup withholding rules that apply to payments of dividends to certain U.S. persons generally will not apply to payments of dividends on our common stock to a Non-U.S. Holder if such Non-U.S. Holder certifies under penalties of perjury that it is not a U.S. person (generally by providing an IRS Form W-8BEN or W-8BEN-E to the applicable withholding agent) or otherwise establishes an exemption.

Proceeds from the sale, exchange or other disposition of our common stock by a Non-U.S. Holder effected outside the United States through a non-U.S. office of a non-U.S. broker generally will not be subject to the information reporting and backup withholding rules that apply to payments to certain U.S. persons, provided that the proceeds are paid to the Non-U.S. Holder outside the United States. However, proceeds from the sale, exchange or other disposition of our common stock by a Non-U.S. Holder effected through a non-U.S. office of a non-U.S. broker with certain specified U.S. connections or a U.S. broker generally will be subject to these information reporting rules (but generally not to these backup withholding rules), even if the proceeds are paid to such Non-U.S. Holder outside the United States, unless such Non-U.S. Holder certifies under penalties of perjury that it is not a U.S. person (generally by providing an IRS Form W-8BEN or W- 8BEN-E to the applicable withholding agent) or otherwise establishes an exemption. Proceeds from the sale, exchange or other disposition of our common stock by a Non-U.S. Holder effected through a U.S. office of a broker generally will be subject to these information reporting and backup withholding rules unless such Non-U.S. Holder certifies under penalties of perjury that it is not a U.S. person (generally by providing an IRS Form W-8BEN or W-8BEN-E to the applicable withholding agent) or otherwise establishes an exemption.

Backup withholding is not an additional tax. Any amounts withheld under the backup withholding rules generally will be allowed as a refund or a credit against a Non-U.S. Holder’s U.S. federal income tax liability if the required information is furnished by such Non-U.S. Holder on a timely basis to the IRS.

U.S. Federal Estate Tax

Shares of our common stock owned or treated as owned by an individual Non-U.S. Holder at the time of such Non-U.S. Holder’s death will be included in such Non-U.S. Holder’s gross estate for U.S. federal estate tax purposes and may be subject to U.S. federal estate tax unless an applicable estate tax treaty provides otherwise.

UNDERWRITING

J.P. Morgan Securities LLC is acting as the underwriter for this offering. United and the selling shareholder will enter into an underwriting agreement with the underwriter. Subject to the terms and conditions of the underwriting agreement, the selling shareholder has agreed to sell to the underwriter, and the underwriter has agreed to purchase from the selling shareholder, 7,300,047 shares of common stock at a price of $ .

The underwriter is committed to purchase all the common shares offered pursuant to this prospectus supplement if it purchases any shares.

The underwriter may offer the shares of common stock from time to time for sale in one or more transactions on the Nasdaq Global Select Market, in the over-the-counter market, through negotiated transactions or otherwise at market prices prevailing at the time of sale or at negotiated prices. The underwriter may effect such transactions by selling shares of common stock to or through dealers, and such dealers may receive compensation in the form of discounts, concessions or commissions from the underwriter and/or purchasers of shares of common stock for whom they may act as agents or to whom they may sell as principal. The difference between the price at which the underwriter purchases shares and the price at which the underwriter resells such shares may be deemed underwriting compensation.

We estimate that the total expenses of this offering payable by us, including registration, filing and listing fees, printing fees and legal and accounting expenses, but excluding the underwriting discounts and commissions, which will be payable by the selling shareholder, will be approximately $ .

A prospectus in electronic format may be made available on the web sites maintained by the underwriter, or selling group members, if any, participating in the offering. The underwriter may agree to allocate a number of shares to the underwriter and selling group members for sale to their online brokerage account holders. Internet distributions will be allocated by the underwriter and selling group members that may make Internet distributions on the same basis as other allocations.

We have agreed that we will not (i) offer, sell, contract to sell, pledge, grant any option to purchase, make any short sale or otherwise transfer or dispose of, or file with the SEC a registration statement under the Exchange Act relating to, any of our securities that are substantially similar to the securities offered hereby, including but not limited to any options or warrants to purchase shares of our common stock or any securities that are convertible into or exchangeable for, or that represent the right to receive, shares of our common stock or any such substantially similar securities or publicly disclose the intention to make any offer, sale, disposition or filing, or (ii) enter into any swap or other agreement that transfers any of the economic consequences of ownership of our common stock or any such other securities (in each case except as provided in the underwriting agreement), in each case without the prior written consent of the underwriter, for a period of 45 days after the date of this prospectus supplement.

The selling shareholder in this offering, our directors and certain of our named executive officers will enter into lock-up agreements with the underwriter pursuant to which each of these persons or entities, with limited exceptions, for a period of 45 days after the date of this prospectus supplement, may not, without the prior written consent of the underwriter, (1) offer for sale, sell, pledge, or otherwise dispose of (or enter into any transaction or device that is designed to, or could reasonably be expected to, result in the disposition by any person any shares of common stock (including, without limitation, shares of common stock that may be deemed to be beneficially owned by the undersigned in accordance with the rules and regulations of the Securities and Exchange Commission and shares of common stock that may be issued upon exercise of any options or warrants) or securities convertible into or exercisable or exchangeable for Common Stock, (2) enter into any swap or other derivatives transaction that transfers to another, in whole or in part, any of the economic benefits or risks of ownership of shares of common stock, whether any such transaction described in clause (1) or (2) above is to be settled by delivery of common stock or other securities, in cash or otherwise, (3) make any demand or exercise any right to file, or cause to be filed, a registration statement, including any amendments thereto, with respect to the registration of any shares of common stock or securities convertible into or exercisable or exchangeable for common stock or any other United Securities or (4) publicly disclose the intention to do any of the foregoing.

We and the selling shareholder have agreed to indemnify the underwriter against certain liabilities, including liabilities under the Securities Act, or contribute payments that the underwriter may be required to make in that respect.

In connection with this offering, the underwriter may engage in stabilizing transactions, which involves making bids for, purchasing and selling shares of common stock in the open market for the purpose of preventing or retarding a decline in the market price of the common stock while this offering is in progress. These stabilizing transactions may include making short sales of the common stock, which involves the sale by the underwriter of a greater number of shares of common stock than they are required to purchase in this offering, and purchasing shares of common stock on the open market to cover positions created by short sales. The underwriter may close out any covered short position by purchasing shares in the open market.

The underwriter has advised us that, pursuant to Regulation M of the Securities Act, it may also engage in other activities that stabilize, maintain or otherwise affect the price of the common stock, including the imposition of penalty bids.

These activities may have the effect of raising or maintaining the market price of the common stock or preventing or retarding a decline in the market price of the common stock, and, as a result, the price of the common stock may be higher than the price that otherwise might exist in the open market. If the underwriter commences these activities, it may discontinue them at any time. The underwriter may carry out these transactions on the Nasdaq Global Select Market, in the over-the-counter market or otherwise.

Other than in the United States, no action has been taken by us or the underwriter that would permit a public offering of the securities offered by this prospectus supplement in any jurisdiction where action for that purpose is required. The securities offered by this prospectus supplement may not be offered or sold, directly or indirectly, nor may this prospectus supplement or any other offering material or advertisements in connection with the offer and sale of any such securities be distributed or published in any jurisdiction, except under circumstances that will result in compliance with the applicable rules and regulations of that jurisdiction. Persons into whose possession this prospectus supplement comes are advised to inform themselves about and to observe any restrictions relating to the offering and the distribution of this prospectus supplement. This prospectus supplement does not constitute an offer to sell or a solicitation of an offer to buy any securities offered by this prospectus supplement in any jurisdiction in which such an offer or a solicitation is unlawful.

Selling Restrictions

United Kingdom

This document is only being distributed to and is only directed at (i) persons who are outside the United Kingdom or (ii) to investment professionals falling within Article 19(5) of the Financial Services and Markets Act 2000 (Financial Promotion) Order 2005, or the “Order,” or (iii) high net worth entities, and other persons to whom it may lawfully be communicated, falling within Article 49(2)(a) to (d) of the Order (all such persons together being referred to as “relevant persons”). The securities are only available to, and any invitation, offer or agreement to subscribe, purchase or otherwise acquire such securities will be engaged in only with, relevant persons. Any person who is not a relevant person should not act or rely on this document or any of its contents.

Switzerland

The shares may not be publicly offered in Switzerland and will not be listed on the SIX Swiss Exchange, or “SIX” or on any other stock exchange or regulated trading facility in Switzerland. This document has been prepared without regard to the disclosure standards for issuance prospectuses under art. 652a or art. 1156 of the Swiss Code of Obligations or the disclosure standards for listing prospectuses under art. 27 ff. of the SIX Listing Rules or the listing rules of any other stock exchange or regulated trading facility in Switzerland. Neither this document nor any other offering or marketing material relating to the shares or the offering may be publicly distributed or otherwise made publicly available in Switzerland.

Neither this document nor any other offering or marketing material relating to the offering, us or the shares have been or will be filed with or approved by any Swiss regulatory authority. In particular, this document will not be filed with, and the offer of shares will not be supervised by, the Swiss Financial Market Supervisory Authority, or “FINMA,” and the offer of shares has not been and will not be authorized under the Swiss Federal Act on Collective Investment Schemes, or “CISA.” The investor protection afforded to acquirers of interests in collective investment schemes under the CISA does not extend to acquirers of shares.

European Economic Area

In relation to each Member State of the European Economic Area that has implemented the Prospectus Directive, each, a “Relevant Member State,” from and including the date that the European Union Prospectus Directive, or the “EU Prospectus Directive,” was implemented in that Relevant Member State, or the “Relevant Implementation Date,” an offer of securities described in this prospectus supplement may not be made to the public in that Relevant Member State prior to the publication of a prospectus in relation to the shares that has been approved by the competent authority in that Relevant Member State or, where appropriate, approved in another Relevant Member State and notified to the competent authority in that Relevant Member State, all in accordance with the EU Prospectus Directive, except that, with effect from and including the Relevant Implementation Date, an offer of securities described in this prospectus supplement may be made to the public in that Relevant Member State at any time:

provided, that no such offer of shares shall require us or the underwriter to publish a prospectus pursuant to Article 3 of the Prospectus Directive or a supplemental prospectus pursuant to Article 16 of the Prospectus Directive.

For the purposes of this provision, the expression an “offer of shares to the public” in relation to any shares in any Relevant Member State means the communication in any form and by any means of sufficient information on the terms of the offer and the shares to be offered so as to enable an investor to decide to purchase or subscribe the shares, as the same may be varied in that Member State by any measure implementing the Prospectus Directive in that Member State, the expression Prospectus Directive means Directive 2003/71/EC (and amendments thereto, including the 2010 PD Amending Directive), and includes any relevant implementing measure in the Relevant Member State and the expression “2010 PD Amending Directive” means Directive 2010/73/EU.

Dubai International Financial Centre

This prospectus supplement relates to an Exempt Offer in accordance with the Offered Securities Rules of the Dubai Financial Services Authority, or “DFSA.” This prospectus supplement is intended for distribution only to persons of a type specified in the Offered Securities Rules of the DFSA. It must not be delivered to, or relied on by, any other person. The DFSA has no responsibility for reviewing or verifying any documents in connection with Exempt Offers. The DFSA has not approved this prospectus supplement nor taken steps to verify the information set forth herein and has no responsibility for the prospectus supplement. The shares to which this prospectus supplement relates may be illiquid and/or subject to restrictions on their resale. Prospective purchasers of the shares offered should conduct their own due diligence on the shares. If you do not understand the contents of this prospectus supplement, you should consult an authorized financial advisor.

Australia

No placement document, prospectus, product disclosure statement or other disclosure document has been lodged with the Australian Securities and Investments Commission (“ASIC”), in relation to the offering. This prospectus supplement does not constitute a prospectus, product disclosure statement or other disclosure document under the Corporations Act 2001 (the “Corporations Act”), and does not purport to include the information required for a prospectus, product disclosure statement or other disclosure document under the Corporations Act.

Any offer in Australia of the shares may only be made to persons (the “Exempt Investors”) who are “sophisticated investors” (within the meaning of section 708(8) of the Corporations Act), “professional investors” (within the meaning of section 708(11) of the Corporations Act) or otherwise pursuant to one or more exemptions contained in section 708 of the Corporations Act so that it is lawful to offer the shares without disclosure to investors under Chapter 6D of the Corporations Act.

The shares applied for by Exempt Investors in Australia must not be offered for sale in Australia in the period of 12 months after the date of allotment under the offering, except in circumstances where disclosure to investors under Chapter 6D of the Corporations Act would not be required pursuant to an exemption under section 708 of the Corporations Act or otherwise or where the offer is pursuant to a disclosure document which complies with Chapter 6D of the Corporations Act. Any person acquiring shares must observe such Australian on-sale restrictions.

This prospectus supplement contains general information only and does not take account of the investment objectives, financial situation or particular needs of any particular person. It does not contain any securities recommendations or financial product advice. Before making an investment decision, investors need to consider whether the information in this prospectus supplement is appropriate to their needs, objectives and circumstances, and, if necessary, seek expert advice on those matters.

Hong Kong

The securities have not been offered or sold and will not be offered or sold in Hong Kong, by means of any document, other than (a) to “professional investors” as defined in the Securities and Futures Ordinance (Cap. 571) of Hong Kong and any rules made under that Ordinance; or (b) in other circumstances which do not result in the document being a “prospectus” as defined in the Companies Ordinance (Cap. 32) of Hong Kong or which do not constitute an offer to the public within the meaning of that Ordinance. No advertisement, invitation or document relating to the securities has been or may be issued or has been or may be in the possession of any person for the purposes of issue, whether in Hong Kong or elsewhere, which is directed at, or the contents of which are likely to be accessed or read by, the public of Hong Kong (except if permitted to do so under the securities laws of Hong Kong) other than with respect to securities which are or are intended to be disposed of only to persons outside Hong Kong or only to “professional investors” as defined in the Securities and Futures Ordinance and any rules made under that Ordinance.

Japan

The securities have not been and will not be registered under the Financial Instruments and Exchange Law of Japan (Law No. 25 of 1948, as amended) and, accordingly, will not be offered or sold, directly or indirectly, in Japan, or for the benefit of any Japanese Person or to others for re-offering or resale, directly or indirectly, in Japan or to any Japanese Person, except in compliance with all applicable laws, regulations and ministerial guidelines promulgated by relevant Japanese governmental or regulatory authorities in effect at the relevant time. For the purposes of this paragraph, “Japanese Person” shall mean any person resident in Japan, including any corporation or other entity organized under the laws of Japan.

Singapore

This prospectus supplement has not been registered as a prospectus with the Monetary Authority of Singapore. Accordingly, this prospectus supplement and any other document or material in connection with the offer or sale, or invitation for subscription or purchase, of Non-CIS Securities may not be circulated or distributed, nor may the Non-CIS Securities be offered or sold, or be made the subject of an invitation for subscription or purchase, whether directly or indirectly, to persons in Singapore other than (i) to an institutional investor under Section 274 of the Securities and Futures Act, Chapter 289 of Singapore, or the “SFA,” (ii) to a relevant person pursuant to Section 275(1), or any person pursuant to Section 275(1A), and in accordance with the conditions specified in Section 275, of the SFA, or (iii) otherwise pursuant to, and in accordance with the conditions of, any other applicable provision of the SFA.

Where the Non-CIS Securities are subscribed or purchased under Section 275 of the SFA by a relevant person which is:

securities (as defined in Section 239(1) of the SFA) of that corporation or the beneficiaries’ rights and interest (howsoever described) in that trust shall not be transferred within six months after that corporation or that trust has acquired the Non-CIS Securities pursuant to an offer made under Section 275 of the SFA except:

Canada

The shares may be sold only to purchasers purchasing, or deemed to be purchasing, as principal that are accredited investors, as defined in National Instrument 45-106 Prospectus Exemptions or subsection 73.3(1) of the Securities Act (Ontario), and are permitted clients, as defined in National Instrument 31-103 Registration Requirements, Exemptions and Ongoing Registrant Obligations. Any resale of the shares must be made in accordance with an exemption from, or in a transaction not subject to, the prospectus requirements of applicable securities laws.

Securities legislation in certain provinces or territories of Canada may provide a purchaser with remedies for rescission or damages if this prospectus supplement (including any amendment thereto) contains a misrepresentation, provided that the remedies for rescission or damages are exercised by the purchaser within the time limit prescribed by the securities legislation of the purchaser’s province or territory. The purchaser should refer to any applicable provisions of the securities legislation of the purchaser’s province or territory for particulars of these rights or consult with a legal advisor.

Pursuant to section 3A.3 of National Instrument 33-105 Underwriting Conflicts, or “NI 33-105,” the underwriter is not required to comply with the disclosure requirements of NI 33-105 regarding underwriter conflicts of interest in connection with this offering.

Other Relationships

The underwriter and its affiliates have provided in the past to us and our affiliates and may provide from time to time in the future certain commercial banking, financial advisory, investment banking and other services for us and such affiliates in the ordinary course of their business, for which they have received and may continue to receive customary fees and commissions. In addition, from time to time, the underwriter and its affiliates may effect transactions for their own account or the account of customers, and hold on behalf of themselves or their customers, long or short positions in our equity securities or loans, and may do so in the future.

LEGAL MATTERS

The validity of the shares of our common stock offered hereby has been passed upon for us by Troutman Sanders LLP, Atlanta, Georgia, and for the underwriter by Kilpatrick Townsend & Stockton LLP, Atlanta, Georgia.

EXPERTS

The consolidated financial statements of United and its subsidiaries as of December 31, 2015 and 2014, and for each of the three years in the period ended December 31, 2015, and management’s assessment of the effectiveness of internal control over financial reporting (which is included in Management’s Report on Internal Control over Financial Reporting) incorporated in this prospectus supplement by reference to the Annual Report on Form 10-K for the year ended December 31, 2015, have been so incorporated in reliance on the report of PricewaterhouseCoopers LLP, an independent registered public accounting firm, given upon the authority of said firm as experts in auditing and accounting.

WHERE YOU CAN FIND MORE INFORMATION

We have filed with the SEC a registration statement on Form S-3 (File No. 333-175226) under the Securities Act of 1933, as amended, with respect to the common stock offered hereby. This prospectus supplement, the accompanying prospectus and the documents incorporated by reference herein and therein are part of a registration statement that we filed with the SEC and do not contain all of the information set forth in the registration statement and the exhibits and schedules thereto. Some items are omitted in accordance with the rules and regulations of the SEC. For further information with respect to us and the common stock offered hereby, we refer you to the registration statement and the exhibits and schedules filed therewith. Statements contained in this prospectus supplement, the accompanying prospectus and the documents incorporated by reference herein and therein as to the contents of any contract, agreement or any other document referred to are summaries of the material terms of the respective contract, agreement or other document. With respect to each of these contracts, agreements or other documents filed as an exhibit to the registration statement or the documents incorporated by reference into this prospectus supplement or the accompanying prospectus, reference is made to the exhibits for a more complete description of the matter involved. A copy of the registration statement and the documents incorporated by reference therein, including the exhibits thereto, may be read and copied at the SEC’s Public Reference Room at 100 F Street, N.E., Room 1580, Washington, D.C. 20549. Information on the operation of the Public Reference Room may be obtained by calling the SEC at 1-800-SEC-0330. In addition, the SEC maintains an internet site at http://www.sec.gov, from which interested persons can electronically access the registration statement, including the exhibits and any schedules thereto. Copies of the registration statement and the documents incorporated by reference therein, including the exhibits and schedules thereto, are also available at your request, without charge, from United Community Banks, Inc., 125 Highway 515 East, Blairsville, Georgia 30512.

We are subject to the informational requirements of the Exchange Act and, accordingly, file annual reports containing financial statements audited by an independent registered public accounting firm, quarterly reports containing unaudited financial statements, current reports, proxy statements and other information with the SEC. You may inspect and copy these reports, proxy statements and other information at the public reference facilities maintained by the SEC at the address noted above. You may also obtain copies of this material from the Public Reference Room of the SEC as described above, or inspect them without charge at the SEC’s website. You may access, free of charge, our reports filed with the SEC (for example, our Annual Reports on Form 10-K, our Quarterly Reports on Form 10-Q and our Current Reports on Form 8-K and any amendments to those forms) through the Investor Relations portion of our website (ir.ucbi.com). Reports filed with or furnished to the SEC will be available as soon as reasonably practicable after they are filed with or furnished to the SEC. None of the information contained on, or that may be accessed through our websites or any other website identified herein is part of, or incorporated into, this prospectus supplement or the accompanying prospectus. All website addresses in this prospectus are intended to be inactive textual references only.

INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

The SEC allows us to “incorporate by reference” into this prospectus supplement and the accompanying prospectus the information that we file with the SEC, which means that we can disclose important information to you by referring you to other documents. The information incorporated by reference is an important part of this prospectus supplement and the accompanying prospectus. We incorporate by reference the following documents:

In addition, all documents we subsequently file pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act after the date of this prospectus supplement will be deemed to be incorporated by reference in this prospectus supplement and the accompanying prospectus and to be a part of this prospectus supplement and the accompanying prospectus from the date of the filing of such documents, until all of the shares of common stock offered by this prospectus supplement have been sold (except to the extent that any information contained in such filings is deemed “furnished” in accordance with SEC rules (unless otherwise indicated therein)).

Any statement contained in a document incorporated or deemed to be incorporated by reference into this prospectus supplement or the accompanying prospectus will be deemed to be modified or superseded for purposes of this prospectus supplement and the accompanying prospectus to the extent that a statement contained in any subsequently filed document that is or is deemed to be incorporated by reference herein or therein modifies or supersedes such prior statement. Any statement so modified or superseded will not be deemed, except as so modified or superseded, to constitute a part of this prospectus supplement and the accompanying prospectus.

Documents incorporated by reference are available from United without charge, excluding all exhibits, unless an exhibit has been specifically incorporated by reference in this prospectus supplement or the accompanying prospectus. You may obtain documents incorporated by reference in this prospectus supplement or the accompanying prospectus by requesting them in writing or by telephone from Lois Rich, Investor Relations, United Community Banks, Inc., at 125 Highway 515 East, Blairsville, Georgia 30512, telephone number (706) 781-2265.

We maintain a website at http://www.ucbi.com where the incorporated documents listed above can be accessed. Neither our website nor the information on our website is included or incorporated in, or is a part of, this prospectus supplement.

TABLE OF CONTENTS

PROSPECTUS

 

Up to 39,999,986 shares of common stock

Up to 15,914,209 shares of non-voting common stock
(which converts into 15,914,209 shares of common stock)

This prospectus relates to the offer and sale by certain selling shareholders identified herein (the “Selling Shareholders”) of up to 39,999,986 shares of our common stock, par value $1.00 per share (the “Common Stock”) and up to 15,914,209 shares of our non-voting common stock, par value $1.00 per share (the “Non-Voting Common Stock”) (which immediately converts at any time and from time to time into 15,914,209 shares of our Common Stock, provided certain conditions are met, as described in this prospectus under “Description of Capital Stock — Non-Voting Common Stock”). We issued the Common Stock and the Non-Voting Common Stock (collectively, the “Securities”) in a private placement to the Selling Shareholders that closed on March 30, 2011 (the “Private Placement”). We are registering the resale of the Securities as required by the investment agreement and subscription agreements (collectively, the “Investment Agreements”) that we entered into with the Selling Shareholders.

The Selling Shareholders may sell all or a portion of the Common Stock from time to time, in amounts, at prices and on terms determined at the time of the offering. Until such time as a market develops for the Non-Voting Common Stock, if any, the Selling Shareholders may sell all or a portion of their shares of the Non-Voting Common Stock from time to time at a price per share that is equal to the lower of  (i) the price per share that any Common Stock is being sold for in the same offering, or (ii) the then-prevailing market price of the Common Stock. Thereafter, the Selling Shareholders may sell all or a portion of their shares of the Non-Voting Common Stock from time to time in negotiated transactions or otherwise, and at prices and on terms that will be determined by the then-prevailing market price of the Non-Voting Common Stock or at negotiated prices. We will not receive any proceeds from the sale of the Securities by the Selling Shareholders. The Securities may be sold by any means described in the section of this prospectus entitled “Plan of Distribution” beginning on page 9.

Our Common Stock is currently traded on the Nasdaq Global Select Market under the symbol “UCBI”. On March 19, 2012, the last reported sale price of our Common Stock on the Nasdaq Global Select Market was $9.55 per share. You are urged to obtain current market quotations of our Common Stock. The Non-Voting Common Stock is not listed on any stock exchange, and we do not intend to list any shares of such stock on a stock exchange. No market currently exists for the Non-Voting Common Stock. When and if a market develops, you are urged to obtain current market quotations of our Non-Voting Common Stock.

​

Investing in the Securities involves a high degree of risk. See the section entitled “Risk Factors” beginning on page 3 and the section entitled “Risk Factors” in our most recent Annual Report on Form 10-K with the Securities and Exchange Commission, which is incorporated herein by reference.

Neither the Securities and Exchange Commission nor any state securities commission or other regulatory body has approved or disapproved of the Securities or passed upon the adequacy or accuracy of this prospectus. Any representation to the contrary is a criminal offense. An investment in the Securities of United Community Banks, Inc. is not insured by the Federal Deposit Insurance Corporation or any other government agency.

The Securities are not deposit accounts and are not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.

​

The date of this prospectus is March 28, 2012

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