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The information in this preliminary prospectus supplement is not complete and may be changed. This preliminary prospectus supplement is part of an effective registration statement filed with the Securities and Exchange Commission. This preliminary prospectus supplement and the accompanying prospectus are not an offer to sell these securities, and neither we nor the selling shareholders are soliciting offers to buy these securities in any jurisdiction where the offer or sale is not permitted.

The selling shareholders listed in this prospectus supplement are offering 11,855,050 shares of our common stock. We will not receive any proceeds from the sale of our common stock by the selling shareholders.

Subject to the completion of this offering, we have agreed to purchase from the underwriters shares of our common stock that are subject to this offering having an aggregate value of approximately $250 million at a price per share equal to the price per share paid by the underwriters to the selling shareholders in this offering.

Investing in our common stock involves risks. See “Risk Factors” beginning on page S-6 of this prospectus supplement and in the documents incorporated by reference herein to read about factors you should consider before buying our common stock.

Our common stock is listed on the New York Stock Exchange (“NYSE”) under the symbol “Q.” On May 13, 2015, the last reported sale price of our common stock on the NYSE was $65.48 per share.

Neither the Securities and Exchange Commission (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 or the accompanying prospectus. Any representation to the contrary is a criminal offense.

The underwriters expect to deliver the shares of common stock against payment in New York, New York on or about , 2015.

This document has two parts, a prospectus supplement and an accompanying prospectus dated November 4, 2014. The accompanying prospectus provides you with a general description of our common stock, which the selling shareholders 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. To the extent the information contained in this prospectus supplement differs or varies from the information contained in the accompanying prospectus or documents incorporated by referenced filed before the date of this prospectus supplement, the information in this prospectus supplement will supersede such information. Before purchasing any of our common stock, you should carefully read both this prospectus supplement, the accompanying prospectus and any applicable free writing prospectus we file with the SEC, together with the additional information described under the headings “Where You Can Find More Information” and “Incorporation of Documents by Reference.”

You should rely only on the information contained or incorporated by reference in this prospectus supplement, the accompanying prospectus or in any applicable free writing prospectus we file with the SEC. Neither we nor the selling shareholders have authorized anyone to provide you with additional or different information. If anyone provides you with additional, different or inconsistent information, you should not rely on it. Neither we nor the selling shareholders will make an offer to sell these securities in any jurisdiction where an offer or sale is not permitted. You should assume that the information appearing in this prospectus supplement, the accompanying prospectus or any applicable free writing prospectus or any of the documents incorporated by reference herein is accurate only as of the respective dates thereof. Our business, financial condition, results of operations and prospects may have changed since those dates.

In this prospectus supplement, unless otherwise stated or the context otherwise requires, references to “Quintiles,” “we,” “us,” “our,” or similar references mean Quintiles Transnational Holdings Inc. and its subsidiaries on a consolidated basis. References to “Quintiles Transnational” mean Quintiles Transnational Corp., Quintiles Transnational Holdings Inc.’s wholly owned subsidiary through which we conduct our operations.

In this prospectus supplement, references to the “Shareholders Agreement” refers to the January 2008 agreement, as subsequently amended and restated, we entered into in connection with a transaction we refer to as the Major Shareholder Reorganization. The Major Shareholder Reorganization resulted in our ownership by Dr. Gillings (and his affiliates), investment funds associated with Bain Capital Investors, LLC, or Bain Capital, affiliates of TPG Global, LLC, or the TPG Funds (we refer to TPG Global, LLC as “TPG Global” and together with its affiliates, “TPG”), affiliates of 3i Corporation, or 3i, certain other shareholders who participated in the going private transaction (including an affiliate of Temasek Holdings (Private) Limited, or Temasek), and various members of our management. “Sponsor” refers to each of the private investment firms of Bain Capital, TPG and 3i, together with any of their respective affiliates who own our shares. Following the completion of our initial public offering, the parties to the Shareholders Agreement consist of Dr. Gillings (and his affiliates) and the Sponsors.

Quintiles^® is our principal registered trademark. This prospectus supplement also includes or incorporates by reference other trademarks and service marks, and those trademarks and service marks are the property of their respective owners.

This prospectus supplement and the documents incorporated herein by reference contain forward-looking statements that reflect, among other things, our current expectations and anticipated results of operations, all of which are subject to known and unknown risks, uncertainties and other factors that may cause our actual results, performance or achievements, market trends, or industry results to differ materially from those expressed or implied by such forward-looking statements. Therefore, any statements contained or incorporated by reference herein that are not statements of historical fact may be forward-looking statements and should be evaluated as such. Without limiting the foregoing, the words “anticipates,” “believes,” “estimates,” “expects,” “intends,” “may,” “plans,” “projects,” “should,” “targets,” “will” and the negative thereof and similar words and expressions are intended to identify forward-looking statements. These forward-looking statements are subject to a number of risks, uncertainties and assumptions, including those described in our Annual Report on Form 10-K for the fiscal year ended December 31, 2014, or our 2014 Form 10-K, which is incorporated by reference in this prospectus supplement, and in the “Risk Factors” section herein. We assume no obligation to update any such forward-looking information to reflect actual results or changes in the factors affecting such forward-looking information.

This prospectus supplement and the documents incorporated by reference herein include market share and industry data and forecasts that we have obtained from market research, consultant surveys, publicly available information and industry publications and surveys, as well as our internal data. Market research, consultant surveys, and industry publications and surveys generally indicate that the information contained therein was obtained from sources believed to be reliable, and we believe that the publications and reports are reliable as of the date of this prospectus supplement. Our internal data, estimates and forecasts are based upon information obtained from our investors, partners, trade and business organizations and other contacts in the markets in which we operate and our management’s understanding of industry conditions. Although we believe that such information included in this prospectus supplement or incorporated by reference herein is reliable, data, forecasts and estimates, in particular as they relate to market size, market growth, penetration, market share and our general expectations, involve risks and uncertainties and are subject to change based on various factors, including those discussed under “Risk Factors” in this prospectus supplement and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” in our 2014 Form 10-K and subsequently filed Quarterly Reports on Form 10-Q. These and other factors could cause actual results to differ materially from those expressed in the estimates made by the independent parties and by us.

PROSPECTUS SUPPLEMENT SUMMARY

This summary highlights information contained elsewhere in this prospectus supplement or incorporated by reference into this prospectus supplement and the accompanying prospectus. This summary is not complete and does not contain all of the information that you should consider before investing in our common stock. Before investing in our common stock, you should carefully read the entire prospectus supplement, the accompanying prospectus, any applicable free writing prospectus we file with the SEC and the information incorporated herein by reference, including the financial data and related notes and the sections entitled “Risk Factors.”

Quintiles

We are the world’s largest provider of biopharmaceutical development services and commercial outsourcing services. We are positioned at the intersection of business services and healthcare and generated $4.2 billion of service revenues in 2014, conduct business in approximately 100 countries and have approximately 33,000 employees. We use the breadth and depth of our service offerings, our global footprint and our therapeutic, scientific and analytics expertise to help our biopharmaceutical customers, as well as other healthcare customers, to be more successful in an increasingly complex healthcare environment.

Our principal executive offices are located at 4820 Emperor Blvd., Durham, North Carolina 27703. Our telephone number at that address is (919) 998-2000. Our common stock is currently traded on the NYSE under the stock symbol “Q.”

Share Repurchase

On April 28, 2015, our board of directors, or our Board, increased the share repurchase authorization under our existing share repurchase program by $300 million for repurchases of our outstanding common stock. The share repurchase program does not obligate us to acquire any particular amount of common stock, has no end date, and may be modified, suspended or discontinued at any time. Subject to the completion of this offering, we have agreed to purchase from the underwriters shares of our common stock that are subject to this offering having an aggregate value of approximately $250 million at a price per share equal to the price per share paid by the underwriters to the selling shareholders in this offering. We refer to this repurchase as the “share repurchase.” We intend to fund the share repurchase with cash on hand. Following the completion of the share repurchase, we will have approximately $109.5 million of remaining availability under our repurchase program.

The description and the other information in this prospectus supplement regarding the share repurchase is included solely for informational purposes. Nothing in this prospectus supplement should be construed as an offer to sell, or the solicitation of an offer to buy, any of our common stock subject to the share repurchase.

The Offering

Common stock being offered by the selling shareholders

11,855,050 shares

Common stock to be outstanding after this offering and the share repurchase

Use of proceeds

We will not receive any of the proceeds from the sale of shares of common stock by the selling shareholders.

Share repurchase

Subject to completion of this offering, we have agreed to repurchase shares of our common stock from the underwriters having an aggregate value of approximately $250 million at a price per share equal to the price paid by the underwriters to the selling shareholders in this offering. The share repurchase was approved by the Audit Committee of our Board, which is comprised entirely of disinterested directors. We intend to fund the share repurchase with cash on hand. See “—Share Repurchase” above.

Risk factors

You should read the “Risk Factors” section in this prospectus supplement and the documents incorporated by reference herein for a discussion of the factors to consider carefully before deciding to purchase any shares of our common stock.

NYSE ticker symbol

“Q.”

The number of shares to be outstanding after this offering and the share repurchase and, unless indicated otherwise, the information in this prospectus supplement (1) is based on 125,109,011 shares of common stock outstanding as of May 11, 2015, which excludes 8,984,782 shares of our common stock issuable upon the exercise of outstanding stock options at a weighted average exercise price of $33.73 per share as of May 11, 2015, of which 4,112,057 were then exercisable, 328,735 shares of common stock issuable upon vesting of certain restricted stock units, 51,977 shares of common stock issuable upon vesting of certain performance units (assuming performance targets are met at 100% of target), and up to 7,118,663 shares of common stock reserved for future issuance under our stock incentive plans, and (2) gives effect to the issuance of 1,000,000 shares pursuant to the exercise of stock options by a selling shareholder in this offering.

Investing in our common stock involves a high degree of risk. You should consider carefully the risks and uncertainties described below together with the other information included in this prospectus supplement, the accompanying prospectus and incorporated by reference herein, before deciding to purchase our common stock. In addition, you should carefully consider, among other things, the section entitled “Risk Factors” beginning on page 21 of our 2014 Form 10-K and in other documents that we subsequently file with the SEC, all of which are incorporated by reference into this prospectus supplement. The risks described below and incorporated herein by reference are those which we believe are the material risks that we face. The occurrence of any of these risks may materially and adversely affect our business, financial condition, results of operations and future prospects. In such an event, the market price of our common stock could decline, and you could lose part or all of your investment.

Although we are no longer a “controlled company” within the meaning of the NYSE rules, we are relying on exemptions from certain corporate governance requirements during a one year transition period.

The parties to the Shareholders Agreement no longer own a majority of our outstanding common stock. As a result, we are no longer a “controlled company” within the meaning of the NYSE corporate governance standards. Pursuant to phase-in periods stipulated by the NYSE Rules, we are required to be in compliance with certain NYSE corporate governance requirements by November 10, 2015, or one year following the date of our loss of “controlled company” status. These requirements include that we have (1) a board that is composed of a majority of “independent directors” as defined under the rules of the NYSE and (2) compensation and nominating and governance committees composed entirely of independent directors.

We have been utilizing, and intend to continue to utilize, the one-year transition period described above to achieve full compliance with these NYSE requirements. As a result, at this time, we do not have a majority of independent directors, and our compensation and nominating and governance committees do not consist entirely of independent directors. Accordingly, you do not, and during this transition period you will not, have the same protections afforded to shareholders of companies that are subject to all of the corporate governance requirements of the NYSE. In addition, if we are unable to comply with the heightened corporate governance requirements prior to the prescribed NYSE deadlines, we may incur penalties or our shares could be delisted.

Provisions of our corporate governance documents could make an acquisition of our company more difficult and may prevent attempts by our shareholders to replace or remove our current management, even if beneficial to our shareholders.

Provisions of our amended and restated articles of incorporation and our amended and restated bylaws may discourage, delay or prevent a merger, acquisition or other change in control of our company that shareholders may consider favorable, including transactions in which you might otherwise receive a premium for your shares. These provisions could also limit the price that investors might be willing to pay in the future for shares of our common stock, thereby depressing the market price of our common stock. In addition, these provisions may frustrate or prevent any attempts by our shareholders to replace or remove members of our Board. Because our Board is responsible for appointing the members of our management team, these provisions could in turn frustrate or prevent any attempt to replace or remove current members of our management team. Among others, these provisions include (1) our ability to issue preferred stock without shareholder approval, (2) the requirement that our shareholders may not act without a meeting, (3) requirements for advance notification of shareholder nominations and proposals contained in our bylaws, (4) the absence of cumulative voting for our directors, (5) requirements for shareholder approval of certain business combinations and (6) the limitations on director nominations contained in our Shareholders Agreement. See “Description of Capital Stock” in the accompanying prospectus and our Current Report on Form 8-K filed on February 6, 2015, which is incorporated by reference herein, for more detail.

Our operating results and share price may be volatile, and the market price of our common stock after this offering may drop below the price you pay.

Our quarterly and annual operating results may fluctuate in the future, and such fluctuations may be significant. In addition, securities markets worldwide have experienced, and are likely to continue to experience, significant price and volume fluctuations. This market volatility, as well as general economic, market or political conditions, could subject the market price of our shares to wide price fluctuations regardless of our operating performance. The selling shareholders and the underwriters will negotiate to determine the public offering price. You may not be able to resell your shares at or above the public offering price or at all. Our operating results and the trading price of our shares may fluctuate in response to various factors, including:

These and other factors, many of which are beyond our control, may cause our operating results and the market price for our shares to fluctuate substantially. While we believe that operating results for any particular quarter are not necessarily a meaningful indication of future results, fluctuations in our quarterly operating results could limit or prevent investors from readily selling their shares and may otherwise negatively affect the market price and liquidity of our shares. In addition, in the past, when the market price of a stock has been volatile, holders of that stock have sometimes instituted securities class action litigation against the company that issued the stock. If any of our shareholders brought a lawsuit against us, we could incur substantial costs defending the lawsuit. Such a lawsuit could also divert the time and attention of our management from our business, which could significantly harm our profitability and reputation.

There may be sales of a substantial amount of our common stock after this offering by our current shareholders, and these sales could cause the price of our common stock to fall.

As of May 11, 2015, there were 125,109,011 shares of common stock outstanding. Approximately 41.3% of our outstanding common stock is held by parties to the Shareholders Agreement. Following completion of this offering and the share repurchase, approximately % of our outstanding common stock will be held by parties to the Shareholders Agreement.

Each of our directors, executive officers and certain significant equity holders (including affiliates of the Sponsors and Temasek) as of the date of this prospectus supplement have entered into a lock-up agreement with the underwriters that regulates their sales of our common stock for a period of 30 days after the date of this prospectus supplement, subject to certain exceptions (including with respect to any shares to be sold in the share repurchase). Following the offering, such lock-up agreements will cover, in the aggregate, 47,151,768 outstanding shares of our common stock and vested options to purchase an additional 2,389,695 shares of our common stock.

Sales of substantial amounts of our common stock in the public market after this offering, or the perception that such sales will occur, could adversely affect the market price of our common stock and make it difficult for us to raise funds through securities offerings in the future. The shares sold in this offering are eligible for immediate sale in the public market without restriction by persons other than our affiliates.

Beginning 90 days after this offering, subject to certain exceptions and automatic extensions in certain circumstances, shareholders that are parties to an amended and restated registration rights agreement, as amended, may require us to effect a public offering of their shares under the federal securities laws so that they can be resold immediately in the public market. Under the registration rights agreement, we are required to pay the registration expenses associated with the public offering of such shares, excluding any underwriting discounts, commissions and transfer taxes. Any such sales or the anticipation of such sales may cause the market price of our common stock to decline.

Since we have no current plans to pay regular cash dividends on our common stock, you may not receive any return on investment unless you sell your common stock for a price greater than that which you paid for it.

Although we have previously declared dividends to our shareholders, we do not currently anticipate paying any regular cash dividends on our common stock. Any decision to declare and pay dividends in the future will be made at the discretion of our Board and will depend on, among other things, our results of operations, financial condition, cash requirements, contractual restrictions and other factors that our Board may deem relevant. In addition, our ability to pay dividends is, and may be, limited by covenants of existing and any future outstanding indebtedness we or our subsidiaries incur, including under our credit facilities. Therefore, any return on investment in our common stock is solely dependent upon the appreciation of the price of our common stock on the open market, which may not occur. See “Dividend Policy” for more detail.

The parties to the Shareholders Agreement will continue to have significant influence over us after this offering, including in connection with decisions that require the approval of our shareholders, which could limit your ability to influence the outcome of matters submitted to shareholders for a vote.

Upon the completion of this offering and the share repurchase, Dr. Gillings (and his affiliates) and the Sponsors will own approximately % of the outstanding shares of our common stock. In addition, these shareholders are and, following the completion of this offering, will continue to be parties to the Shareholders Agreement which, among other things, requires such shareholders to vote in favor of certain nominees to our Board. For a discussion of the Shareholders Agreement and these nominating rights, see our Current Report on Form 8-K filed with the SEC on February 6, 2015, which is incorporated by reference herein. As a result, this group potentially has the ability to influence or effectively control our decisions to enter into any corporate transaction (and the terms thereof) and the ability to prevent any change in the composition of our Board and any transaction that requires shareholder approval regardless of whether others believe that such change or transaction is in our best interests. Additionally, the Sponsors are in the business of making investments in companies and may from time to time acquire and hold interests in businesses that compete directly or indirectly with us. One or more of the Sponsors may also pursue acquisition opportunities that may be complementary to our business and, as a result, those acquisition opportunities may not be available to us. So long as the parties to the Shareholders Agreement continue to own a significant amount of our equity, if they exercise their shareholder rights collectively, they would be able to significantly influence our decisions.

Following our debt refinancing completed on May 12, 2015, we have $2,525 million of total indebtedness, excluding the ability to borrow an additional $534 million, net of bank guarantees of $5.7 million, including $500 million under a revolving credit facility and $25 million of additional available borrowings under our receivables financing facility. Our substantial indebtedness could adversely affect our financial condition and

thus make it more difficult for us to satisfy our obligations with respect to our indebtedness. If our cash flow is not sufficient to service our debt and adequately fund our business, we may be required to seek further additional financing or refinancing or dispose of assets. We may not be able to implement any of these alternatives on satisfactory terms or at all. Our substantial indebtedness could also:

We will not receive any of the proceeds from the sale of shares of our common stock by the selling shareholders in this offering.

The following table sets forth our cash and cash equivalents and capitalization as of March 31, 2015, on:

You should read this information in conjunction with the sections entitled “Prospectus Summary” and “Description of Capital Stock” included elsewhere in this prospectus supplement and the accompanying prospectus, as well as “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and consolidated financial statements in our 2014 Form 10-K and subsequently filed Quarterly Reports on Form 10-Q, which are incorporated by reference herein.

The following table sets forth information with respect to the beneficial ownership of our common stock as of May 11, 2015 for each selling shareholder.

Except as otherwise indicated, to our knowledge, the persons named in the table below have sole voting and investment power with respect to all shares of common stock shown as beneficially owned by them, subject to community property laws, where applicable.

The number of shares beneficially owned by each shareholder is determined pursuant to Rule 13d-3 promulgated by the SEC under the Securities Exchange Act of 1934, as amended, or the Exchange Act. The information does not necessarily indicate beneficial ownership for any other purpose. Under those rules, the number of shares of common stock deemed outstanding includes shares issuable upon exercise of stock options held by the respective person or group that may be exercised within 60 days of May 11, 2015. For purposes of calculating each person’s or group’s percentage ownership, shares of common stock issuable pursuant to stock options exercisable within 60 days after May 11, 2015 are reflected in the table below and included as outstanding and beneficially owned for that person or group but are not treated as outstanding for the purpose of computing the percentage ownership of any other person or group.

The number of shares and percentages of beneficial ownership prior to this offering and the share repurchase set forth below are based on the number of shares of our common stock issued and outstanding immediately prior to the consummation of this offering and the share repurchase. The number of shares and percentages of beneficial ownership after this offering and the share repurchase set forth below are based on the number of shares of our common stock issued and outstanding immediately after the completion of this offering and the share repurchase assuming the selling shareholders sell 11,855,050 shares of common stock offered by this prospectus supplement, including 1,000,000 shares issued upon the exercise of outstanding options by one of the selling shareholders, and assuming that the share repurchase of shares is consummated shortly after completion of this offering.

The percentages of shares outstanding provided in the table are based on a total of 125,109,011 shares of our common stock outstanding on May 11, 2015.

For more information regarding our relationships with certain of the persons named below, see “Certain Relationships and Related Person Transactions” in our Proxy Statement for our 2015 Annual Meeting of Shareholders filed with the SEC on March 23, 2015.

Notwithstanding the ownership information regarding our common stock presented below, the Shareholders Agreement governs the exercise of the voting rights of the shareholders party thereto with respect to the election of directors and certain other material events. See our Current Report on Form 8-K filed on February 6, 2015, which is incorporated by reference herein, for further information.

The following is a summary of the material United States federal income and estate tax consequences to non-United States holders of the purchase, ownership and disposition of our common stock as of the date hereof. Except where noted, this summary deals only with common stock purchased in this offering that is held as a capital asset by a non-United States holder.

Except as modified for estate tax purposes, a “non-United States holder” means a beneficial owner of our common stock that is not, for United States federal income tax purposes, any of the following:

This summary is based upon provisions of the Internal Revenue Code of 1986, as amended, or the Code, and applicable United States Treasury regulations promulgated or proposed thereunder and administrative and judicial interpretations thereof, all as of the date hereof. Those authorities may be changed, perhaps retroactively, so as to result in United States federal income and estate tax consequences different from those summarized below. This summary does not address all aspects of United States federal income and estate taxes and does not deal with foreign, state, local or other tax considerations that may be relevant to non-United States holders in light of their particular circumstances. In addition, it does not represent a detailed description of the United States federal income or estate tax consequences applicable to you if you are subject to special treatment under the United States federal income or estate tax laws (including if you are a financial institution, United States expatriate, “controlled foreign corporation,” “passive foreign investment company,” person subject to the alternative minimum tax, dealer in securities, broker, person who has acquired our common stock as part of a straddle, hedge, conversion transaction or other integrated investment, or a partnership or other pass-through entity for United States federal income tax purposes (or an investor in such a pass-through entity)). We cannot assure you that a change in law will not alter significantly the tax considerations that we describe in this summary.

We have not and will not seek any rulings from the Internal Revenue Service, or IRS, regarding the matters discussed below. There can be no assurance that the IRS will not take positions concerning the tax consequences of the purchase, ownership or disposition of shares of our common stock that are different from those discussed below.

If any entity or arrangement treated as a partnership for United States federal income tax purposes holds our common stock, the tax treatment of a partner will generally depend upon the status of the partner and the activities of the partnership and upon certain determinations made at the partner level. If you are a partner of a partnership holding our common stock, you should consult your tax advisors.

If you are considering the purchase of our common stock, you should consult your own tax advisors concerning the particular United States federal income and estate tax consequences to you of the purchase, ownership and disposition of our common stock, as well as the consequences to you arising under the laws of any other applicable taxing jurisdiction, in light of your particular circumstances.

If we make distributions on our common stock, those payments will constitute dividends for United States federal income tax purposes to the extent paid from our current or accumulated earnings and profits, as determined under United States federal income tax principles. To the extent those distributions exceed both our current and our accumulated earnings and profits, they will constitute a return of capital and will first reduce your basis in our common stock (determined on a share by share basis), but not below zero. Any excess will be treated as gain from the sale of stock subject to the tax treatment described below in “Gain on Disposition of Common Stock.”

In the event that we pay dividends on our common stock, the dividends paid to a non-United States holder generally will be subject to withholding of United States federal income tax at a 30% rate, or such lower rate as may be specified by an applicable income tax treaty, on the gross amount of the dividends paid. However, dividends that are effectively connected with the conduct of a trade or business by the non-United States holder within the United States (and, if an applicable income tax treaty so provides, that are attributable to a permanent establishment of such non-United States holders within the United States) generally are not subject to the withholding tax, provided certain certification and disclosure requirements are satisfied. Instead, such dividends are generally subject to United States federal income tax on a net income basis in the same manner as if the non-United States holder were a United States person as defined under the Code (unless an applicable income tax treaty provides otherwise). A foreign corporation may be subject to an additional “branch profits tax” at a 30% rate (or such lower rate as may be specified by an applicable income tax treaty) on its effectively connected earnings and profits attributable to such dividends.

A non-United States holder of our common stock who wishes to claim the benefit of an applicable treaty rate and avoid backup withholding, as discussed below, for dividends generally will be required (a) to complete IRS Form W-8BEN, in the case of a beneficial owner that is an individual, or W-8BEN-E, in the case of a beneficial owner that is an entity, (or other applicable form) and certify under penalty of perjury that such holder is not a United States person as defined under the Code and is eligible for treaty benefits or (b) if our common stock is held through certain foreign intermediaries, to satisfy the relevant certification requirements of applicable United States Treasury regulations. Special certification and other requirements apply to certain non-United States holders that are pass-through entities rather than corporations or individuals.

A non-United States holder of our common stock eligible for a reduced rate of United States withholding tax pursuant to an income tax treaty may obtain a refund of any excess amounts withheld by timely filing an appropriate claim for refund with the IRS.

Any gain realized by a non-United States holder on the disposition of our common stock generally will not be subject to United States federal income tax unless:

In the case of a non-United States holder described in the first bullet point immediately above, the gain will be subject to United States federal income tax on a net income basis generally in the same manner as if the non-United States holder were a United States person as defined under the Code (unless an applicable income tax treaty provides otherwise), and a non-United States holder that is a foreign corporation may be subject to a branch profits tax equal to 30% of its effectively connected earnings and profits attributable to such gain (or at such lower rate as may be specified by an applicable income tax treaty). In the case of an individual non-United States holder described in the second bullet point immediately above, except as otherwise provided by an applicable income tax treaty, the gain, which may be offset by United States source capital losses, will be subject to a flat 30% tax even though the individual is not considered a resident of the United States under the Code.

We believe we are not and do not anticipate becoming a “United States real property holding corporation” for United States federal income tax purposes. If, however, we are or become a “United States real property holding corporation,” so long as our common stock is regularly traded on an established securities market, only a non-United States holder who actually or constructively holds or held (at any time during the shorter of the five year period ending on the date of disposition or the non-United States holder’s holding period) more than 5% of our common stock will be subject to United States federal income tax on the disposition of our common stock as a result of our being a United States real property holding corporation. You should consult your own advisor about the consequences that could result if we are, or become, a “United States real property holding corporation.”

We must report annually to the IRS and to each non-United States holder the amount of dividends paid to such holder and the tax withheld with respect to such dividends, regardless of whether withholding was required. Copies of the information returns reporting such dividends and withholding may also be made available to the tax authorities in the country in which the non-United States holder resides under the provisions of an applicable income tax treaty or agreement.

A non-United States holder will be subject to backup withholding for dividends paid to such holder unless such holder certifies under penalty of perjury that it is a non-United States holder (and the payer does not have actual knowledge or reason to know that such holder is a United States person as defined under the Code), or such holder otherwise establishes an exemption.

Information reporting and, depending on the circumstances, backup withholding will apply to the proceeds of a sale of our common stock within the United States or conducted through certain United States-related financial intermediaries, unless the beneficial owner certifies under penalty of perjury that it is a non-United States holder (and the payer does not have actual knowledge or reason to know that the beneficial owner is a United States person as defined under the Code), or such owner otherwise establishes an exemption.

Any amounts withheld under the backup withholding rules may be allowed as a refund or a credit against a non-United States holder’s United States federal income tax liability provided the required information is timely furnished to the IRS.

The Foreign Account Tax Compliance Act, or FATCA, imposes a United States federal withholding tax at a rate of 30% on payments of dividends on our common stock and, for a sale or other disposition of our common stock occurring after December 31, 2016, on payments of gross proceeds from such sale or other disposition, in each case where such payment is made to (1) a foreign financial institution (whether holding stock for its own account or on behalf of one or more of its account holders/investors), unless such foreign financial institution agrees to verify, report and disclose its United States account holders and meets certain other specified requirements or (2) a non-financial foreign entity that is the beneficial owner of the payment (or who holds stock on behalf of another non-financial foreign entity that is the beneficial owner), unless the beneficial owner

certifies that it does not have any substantial United States owners or provides the name, address and taxpayer identification number of each substantial United States owner and meets certain other specified requirements. Prospective investors are encouraged to consult with their own tax advisors regarding the possible implications of these withholding requirements on their investment in our common stock.

Our common stock that is owned (or treated as owned) by an individual who is not a citizen or resident of the United States (as specially defined for United States federal estate tax purposes) at the time of death will be included in such individual’s gross estate for United States federal estate tax purposes, unless an applicable estate or other tax treaty provides otherwise, and, therefore, may be subject to United States federal estate tax.

The underwriters named below, the selling shareholders and Quintiles have entered into an underwriting agreement with respect to the shares of common stock being offered hereby. Subject to certain conditions, the underwriters have severally agreed to purchase the number of shares of common stock indicated in the following table from the selling shareholders.

The underwriters are committed to take and pay for all of the shares of common stock being offered, if any are taken.

Subject to the completion of this offering, we have agreed to purchase from the underwriters shares of our common stock that are subject to this offering having an aggregate value of approximately $250 million at a price per share equal to the price paid by the underwriters to the selling shareholders in this offering.

The following table shows the per share and total underwriting discounts and commissions to be paid to the underwriters by the selling shareholders.

Shares of common stock sold by the underwriters to the public will initially be offered at the initial public offering price set forth on the cover of this prospectus supplement. Any shares of common stock sold by the underwriters to securities dealers may be sold at a discount of up to $ per share from the initial public offering price. If all the shares of common stock are not sold at the initial public offering price, the underwriters may change the offering price and the other selling terms. The offering of the shares of common stock by the underwriters is subject to receipt and acceptance and subject to the underwriters’ right to reject any order in whole or in part.

We have agreed that, subject to certain exceptions, we will not (i) offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, lend or otherwise transfer or dispose of, directly or indirectly, any shares of common stock or any other securities convertible into or exercisable or exchangeable for shares of common stock, or (ii) enter into any swap or other arrangement that transfers to another, in whole or in part, any of the economic consequences of ownership of the common stock (regardless of whether any such transactions described in clause (i) or (ii) above is to be settled by delivery of common stock or such other securities, in cash or otherwise), or (iii) file any registration statement with the SEC relating to the offering of any shares of common stock or any securities convertible into or exercisable or exchangeable for common stock (other than on Form S-8), in each case without the prior written consent of the underwriters for a period of 30 days after the date of this prospectus supplement.

Each of our shareholders subject to our Shareholders Agreement, each of the selling shareholders and each of our directors and executive officers as of the date of this prospectus supplement have entered into lock-up agreements with the underwriters prior to the commencement of this offering pursuant to which, for a period of 30 days after the date of this prospectus supplement each of these persons or entities, with limited exceptions, may not, without the prior written consent of the representatives, (i) offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, lend or otherwise transfer or dispose of, directly or indirectly, any shares of our common stock, or any securities convertible into or exercisable or exchangeable for our common stock, beneficially owned (as such term is used in Rule 13d-3 under the Exchange Act) by such directors, executive officers, and selling

shareholders or (ii) enter into any swap or other arrangement that transfers to another, in whole or in part, any of the economic consequences of ownership of the common stock (regardless of whether any of these transactions described in clause (i) or (ii) above are to be settled by the delivery of shares of common stock or such other securities, in cash or otherwise) or (iii) make any demand for or exercise any right with respect to the registration of any shares of our common stock or any security convertible into or exercisable for our common stock.

In connection with this offering, the underwriters 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 underwriters of a greater number of shares of common stock than it is required to purchase in this offering, and purchasing shares of common stock on the open market to cover positions created by short sales.

The underwriters have advised us that, pursuant to Regulation M of the Securities Act, they may also engage in other activities that stabilize, maintain or otherwise affect the price of the common stock.

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 underwriters commence these activities, they may discontinue them at any time. The underwriters may carry out these transactions on the NYSE, in the over-the-counter market or otherwise.

We estimate that our portion of the total expenses of the offering, excluding underwriting discounts and commissions, will be approximately $500,000.

The selling shareholders and the underwriters have agreed to severally indemnify each other against certain liabilities, including liabilities under the Securities Act.

Other than in the United States, no action has been taken by us or the underwriters 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 this 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.

The underwriters and their affiliates have provided and may provide from time to time in the future certain commercial banking, financial advisory, investment banking and other services for us in the ordinary course of their business, for which they have received and may continue to receive customary fees and commissions. The underwriters or one or more of their affiliates are lenders, co-documentation agents and/or joint bookrunners for our credit facilities and the underwriters or their affiliates acted as initial purchasers with respect to our recent offering of senior notes. From time to time, the underwriters and their 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 debt or equity securities or loans, and may do so in the future. Such investments and securities activities may involve securities and/or instruments of ours or our affiliates. The underwriters or their affiliates may also make investment recommendations and/or publish or express independent research views in respect of such securities or financial instruments and may hold, or recommend to customers that they acquire, long and/or short positions in such securities and instruments.

In relation to each member state of the European Economic Area that has implemented the Prospectus Directive (each, a relevant member state), with effect from and including the date on which the Prospectus Directive, as defined below, is implemented in that relevant member state (the relevant implementation date), an offer of shares described in this prospectus supplement may not be made to the public in that relevant member state other than:

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

For purposes of this provision, the expression an “offer of securities to the public” 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 for the shares, as the expression may be varied in that member state by any measure implementing the Prospectus Directive in that member state, and the expression “Prospectus Directive” means Directive 2003/71/EC (and amendments thereto, including the 2010 PD Amending Directive, to the extent implemented in the relevant member state) and includes any relevant implementing measure in the relevant member state. The expression 2010 PD Amending Directive means Directive 2010/73/EU.

The sellers of the shares have not authorized and do not authorize the making of any offer of shares through any financial intermediary on their behalf, other than offers made by the underwriters with a view to the final placement of the shares as contemplated in this prospectus supplement. Accordingly, no purchaser of the shares, other than the underwriters, is authorized to make any further offer of the shares on behalf of the sellers or the underwriters.

This prospectus supplement is only being distributed to, and is only directed at, persons in the United Kingdom that are qualified investors within the meaning of Article 2(1)(e) of the Prospectus Directive, which we

refer to as Qualified Investors, that are also (i) investment professionals falling within Article 19(5) of the Financial Services and Markets Act 2000 (Financial Promotion) Order 2005, which we refer to as the Order, or (ii) high net worth entities, falling within Article 49(2)(a) to (d) of the Order, and (iii) any other person to whom it may lawfully be communicated pursuant to the Order, all such persons which we refer to together as relevant persons. This prospectus supplement and its contents are confidential and should not be distributed, published or reproduced (in whole or in part) or disclosed by recipients to any other persons in the United Kingdom. Any investment activity to which this prospectus supplement relates will only be available to, and will only be engaged with, relevant persons. Any person in the United Kingdom that is not a relevant person should not act or rely on this document or any of its contents.

All applicable provisions of the Financial Services and Markets Act 2000 (as amended) must be complied with in respect to anything done by any person in relation to our common stock in, from or otherwise involving the United Kingdom.

The shares of common stock are not being offered to the public in Switzerland. Therefore, this document constitutes neither a public offer in Switzerland nor a prospectus supplement in accordance with applicable legislation in Switzerland and may not be issued, distributed or published in Switzerland in a manner which would be deemed to constitute a public offer of the shares of common stock in Switzerland.

This prospectus supplement has not been approved by or registered with the Securities and Futures Commission of Hong Kong or the Registrar of Companies of Hong Kong. No person may offer or sell in Hong Kong, by means of any document, any Shares other than (i) to “professional investors” as defined in the Securities and Futures Ordinance (Cap. 571) of Hong Kong and any rules made under that Ordinance, or (ii) 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 person may issue or have in its possession for the purposes of issue, whether in Hong Kong or elsewhere, any advertisement, invitation or document relating to the Shares 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 Shares 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.

The shares of common stock have not been and will not be registered under the Financial Instruments and Exchange Law, as amended (the “FIEL”). The underwriters have represented and agreed that the Shares which it purchases will be purchased by it as principal and that, in connection with this offering, it will not, directly or indirectly, offer or sell any Shares in Japan or to, or for the benefit of, any resident of Japan (which term as used herein means any person resident in Japan, including any corporation or entity organized under the laws of Japan) or to others for reoffer or resale, directly or indirectly, in Japan or to, or for the benefit of, any resident of Japan, except pursuant to an exemption from the registration requirements under the FIEL and otherwise in compliance with such law and any other applicable laws, regulations and ministerial guidelines of Japan.

This prospectus supplement has not been registered as a prospectus with the Monetary Authority of Singapore under the Securities and Futures Act, Chapter 289 of Singapore, or the SFA. Accordingly, no person may offer or sell such Shares or cause such Shares to be made the subject of an invitation for subscription or purchase, or circulate or distribute, this prospectus supplement or any other document or material in connection

with the offer or sale, or invitation for subscription or purchase, of such Shares, whether directly or indirectly, to persons in Singapore other than (i) to an institutional investor under Section 274 of the SFA, (ii) to a relevant person pursuant to Section 275(1), or (iii) to any person pursuant to Section 275(1A), and in accordance with the conditions specified in Section 275 of the SFA, or otherwise pursuant to, and in accordance with the conditions of, any other applicable provision of the SFA.

This prospectus supplement relates to an Exempt Offer in accordance with the Offered Securities Rules of the Dubai Financial Services Authority (“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.

Certain legal matters in connection with this offering will be passed upon for us by Smith, Anderson, Blount, Dorsett, Mitchell & Jernigan, L.L.P., Raleigh, North Carolina. Certain legal matters in connection with this offering will be passed upon for the underwriters by White & Case LLP, New York, New York.

The financial statements 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, 2014 have been so incorporated in reliance on the report of PricewaterhouseCoopers LLP, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting.

This prospectus supplement, which constitutes part of a registration statement we filed with the SEC, does not include all of the information contained in the registration statement and the exhibits to the registration statement. For further information with respect to us and our common stock, you should refer to the registration statement (including this prospectus supplement and the accompanying prospectus), the exhibits to the registration statement and the documents incorporated by reference in this prospectus supplement. Statements contained in this prospectus supplement about the contents of any contract or any other document are not necessarily complete, and in each instance, we refer you to the copy of the contract or other documents filed as an exhibit to the registration statement. Each of these statements is qualified in all respects by this reference.

We are subject to the informational requirements of the Exchange Act and, in accordance therewith, we file reports and other information with the SEC. You may read and copy the registration statement of which this prospectus supplement is a part, such reports and other information at the SEC’s public reference room, which is located at 100 F Street, NE, Room 1580, Washington, D.C. 20549, on official business days during the hours of 10:00 a.m. to 3:00 p.m. You can request copies of these documents by writing to the SEC and paying a fee for

the copying cost. Please call the SEC at 1-800-SEC-0330 for more information about the operation of the SEC’s public reference room. In addition, the SEC maintains an Internet website, which is located at http://www.sec.gov, that contains reports, proxy and information statements and other information regarding issuers that file electronically with the SEC. You may access the registration statement of which this prospectus supplement is a part and the other reports and information that we have filed with the SEC at the SEC’s Internet website.

The SEC allows us to “incorporate by reference” information we file with it into our registration statement of which this prospectus supplement is a part, 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.

The following documents filed with the SEC are hereby incorporated by reference in this registration statement:

However, any portions of the above-referenced documents that are not deemed “filed” with the SEC, including without limitation the certifications required by Rule 13a-14(b) or Rule 15d-14(b) under the Exchange Act, any information furnished pursuant to Item 2.02 or 7.01 of Form 8-K and certain exhibits furnished pursuant to Item 9.01 of Form 8-K, shall not be deemed to be incorporated by reference in this registration statement.

We will provide to each person, including any beneficial owners, to whom a prospectus supplement is delivered, upon written or oral request of any such person, a copy of the reports and documents that have been incorporated by reference into this prospectus supplement, at no cost. Any such request should be directed to: Quintiles Transnational Holdings Inc., 4280 Emperor Blvd., Durham, North Carolina 27703, Attention: General Counsel, (919) 998-2000, officeofgeneralcounsel@quintiles.com. These documents are also available on the Investor Relations section of our website, which is located at http://www.quintiles.com, or as described under “Where You Can Find Additional Information” above. The reference to our website address does not constitute incorporation by reference of the information contained on our website.

Any statement in a document incorporated or deemed to be incorporated by reference herein shall be deemed to be modified or superseded for the purposes of this registration statement to the extent that a statement contained herein modifies or supersedes such statement. Any statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this registration statement.

We may offer and sell shares of our common stock from time to time in amounts, at prices and on terms that will be determined at the time of the offering. The selling shareholders to be named in a prospectus supplement may also offer and sell shares of our common stock from time to time in one or more offerings. We will not receive any of the proceeds from the sale of our common stock by selling shareholders.

This prospectus describes the general manner in which the shares of our common stock may be offered and sold. The specific manner in which shares of common stock may be offered and sold will be described in a supplement to this prospectus. In the case of an offering by selling shareholders, information about the selling shareholders, including the relationship between the selling shareholders and us, will also be included in the applicable prospectus supplement.

You should carefully read this prospectus and any accompanying prospectus supplement, together with the documents we incorporate by reference, before you invest in our common stock.

Investing in our common stock involves risks. See “Risk Factors” beginning on page 1 to read about factors you should consider before buying our common stock.

Our common stock is listed on the New York Stock Exchange (“NYSE”) under the symbol “Q.” On October 31, 2014, the last reported sale price of our common stock on the NYSE was $58.54 per share.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus. Any representation to the contrary is a criminal offense.

This prospectus is part of a registration statement on Form S-3 that we filed with the United States Securities and Exchange Commission, or the SEC, as a “well-known seasoned issuer” as defined under Rule 405 under the Securities Act of 1933, as amended, or the Securities Act, using a “shelf” registration process. By using a shelf registration statement, we and/or the selling shareholders to be named in a supplement to this prospectus may, from time to time, sell shares of our common stock in one or more offerings. Each time that we and/or the selling shareholders sell securities under this shelf registration statement, we will provide a prospectus supplement that will contain specific information about the terms of that offering. A prospectus supplement may also add, update or change information contained in this prospectus with respect to that offering, including information about the selling shareholders. If there is any inconsistency between the information in this prospectus and an applicable prospectus supplement, you should rely on the prospectus supplement. Before purchasing any securities, you should carefully read both this prospectus and any applicable prospectus supplement or free writing prospectus we file with the SEC, together with the additional information described under the headings “Where You Can Find More Information” and “Incorporation by Reference.”

You should rely only on the information contained or incorporated by reference in this prospectus, any accompanying prospectus supplement or any applicable free writing prospectus we file with the SEC. Neither we nor the selling shareholders have authorized anyone to provide you with additional or different information. If anyone provides you with additional or different information, you should not rely on it. Neither we nor the selling shareholders will make an offer to sell these securities in any jurisdiction where an offer or sale is not permitted. You should not assume that the information in this prospectus or in the documents incorporated by reference is accurate as of any date other than the date on the front of such documents. Our business, financial condition, results of operations and prospects may have changed since that date.

In this prospectus, unless otherwise stated or the context otherwise requires, references to “Quintiles,” “we,” “us,” “our,” or similar references mean Quintiles Transnational Holdings Inc. and its subsidiaries on a consolidated basis. References to “Quintiles Holdings” refer to Quintiles Transnational Holdings Inc. on an unconsolidated basis. References to “Quintiles Transnational” refer to Quintiles Transnational Corp., Quintiles Holdings’ wholly-owned subsidiary through which we conduct our operations.

In this prospectus, unless otherwise stated or the context otherwise requires, references to the “Shareholders Agreement” refers to the January 2008 agreement, as amended, we entered into in connection with a shareholder reorganization that resulted in our ownership by our founder, Dennis B. Gillings, CBE, Ph.D. (and his affiliates), investment funds associated with Bain Capital Investors, LLC, or Bain Capital, affiliates of TPG Global, LLC, collectively, TPG, affiliates of 3i Corporation, or 3i, certain other shareholders who participated in the going private transaction (including an affiliate of Temasek Holdings (Private) Limited), and various members of our management. “Sponsor” refers to each of the private investment firms of Bain Capital, TPG, and 3i, together with any of their respective affiliates who own our shares. Following the completion of our initial public offering, the parties to the Shareholders Agreement consist of Dr. Gillings (and his affiliates) and the Sponsors.

Quintiles^® is our principal registered trademark. This prospectus also includes or incorporates by reference other trademarks and service marks, and those trademarks and service marks are the property of their respective owners.

Investing in our common stock involves a high degree of risk. You should consider carefully the risks and uncertainties described in “Risk Factors” and elsewhere in our most recently filed Annual Report on Form 10-K and in any subsequent filings, which are incorporated by reference in this prospectus. The prospectus supplement relating to a particular offering of common stock may also discuss certain risks of investing in that offering. The occurrence of any of such risks may materially and adversely affect our business, financial condition, results of operations and future prospects. In such an event, the market price of our common stock could decline, and you could lose part or all of your investment.

Certain statements regarding our future performance that are contained or incorporated by reference in this prospectus or any prospectus supplement constitute “forward-looking statements” as defined in the Private Securities Litigation Reform Act of 1995. Forward-looking statements may relate to, among other things, our current expectations and anticipated results of operations, all of which are subject to known and unknown risks, uncertainties and other factors that may cause our actual results, performance or achievements, market trends, or industry results to differ materially from those expressed or implied by such forward-looking statements. Therefore, any statements contained or incorporated by reference herein that are not statements of historical fact may be forward-looking statements and should be evaluated as such. Without limiting the foregoing, the words “anticipates,” “believes,” “estimates,” “expects,” “intends,” “may,” “plans,” “projects,” “should,” “targets,” “will” and the negative thereof and similar words and expressions are intended to identify forward-looking statements. We assume no obligation to update any such forward-looking information to reflect actual results or changes in the factors affecting such forward-looking information.

We caution you that any such forward-looking statements are further qualified by important factors that could cause our actual operating results to differ materially from those in the forward-looking statements, including without limitation, that most of our contracts may be terminated on short notice, and we may be unable to maintain large customer contracts or to enter into new contracts; our financial results may be adversely affected if we underprice our contracts, overrun our cost estimates or fail to receive approval for or experience delays in documenting change orders; the historical indications of the relationship of our backlog to revenues may not be indicative of their future relationship; we may be unable to maintain our information systems or effectively update them; customer or therapeutic concentration could harm our business; our business is subject to risks associated with international operations, including economic, political and other risks, such as compliance with a myriad of laws and regulations, complications from conducting clinical trials in multiple countries simultaneously and changes in exchange rates; the market for our services may not grow as we expect; government regulators or our customers may limit the scope of prescription or withdraw products from the market, and government regulators may impose new regulatory requirements or may adopt new regulations affecting the biopharmaceutical industry; we may be unable to successfully develop and market new services or enter new markets; our failure to perform services in accordance with contractual requirements, regulatory standards and ethical considerations may subject us to significant costs or liability, which could also damage our reputation and cause us to lose existing business or not receive new business; our services are related to treatment of human patients, and we could face liability if a patient is harmed; we may be unable to successfully identify, acquire and integrate businesses, services and technologies; and we have substantial indebtedness and may incur additional indebtedness in the future, which could adversely affect our financial condition. For a further discussion of the risks relating to our business, see “Risk Factors” in our Annual Report on Form 10-K for the fiscal year ended December 31, 2013, as amended, or our 2013 Form 10-K, which is incorporated by reference in this prospectus and in the “Risk Factors” section in the applicable prospectus supplement.

We are the world’s largest provider of biopharmaceutical development services and commercial outsourcing services. We are positioned at the intersection of business services and healthcare and generated $3.8 billion of service revenues in 2013, conduct business in approximately 100 countries and have more than 32,000 employees. We use the breadth and depth of our service offerings, our global footprint and our therapeutic, scientific and analytics expertise to help our biopharmaceutical customers, as well as other healthcare customers, navigate an increasingly complex healthcare environment as they seek to improve efficiency and effectiveness in the delivery of better healthcare outcomes.

Unless otherwise specified in connection with a particular offering of securities, we will use the net proceeds from the sale of our common stock offered by this prospectus for general corporate purposes. Unless otherwise set forth in a prospectus supplement, we will not receive any proceeds from the sale of our common stock by any selling shareholders.

Selling shareholders are persons or entities that, directly or indirectly, have acquired or will from time to time acquire from us, common shares in various private transactions. Such selling shareholders may be parties to registration rights agreements with us, or we otherwise may have agreed or will agree to register their securities for resale. The initial purchasers of our securities, as well as their transferees, pledgees, donees or successors, all of whom we refer to as “selling shareholders,” may from time to time offer and sell the securities pursuant to this prospectus and any applicable prospectus supplement.

The applicable prospectus supplement will set forth the name of each participating selling shareholder and the number of common shares beneficially owned by such selling shareholder prior to the offering covered by such prospectus supplement, the number of common shares owned by such selling shareholder that are offered for the selling shareholder’s account in the prospectus supplement and the amount and (if more than one percent) the percentage of our common shares to be owned by such selling shareholder after completion of the offering. The applicable prospectus supplement will also disclose whether any of the participating selling shareholders has held any position or office with, has been employed by or otherwise has had a material relationship with us or any of our predecessors or affiliates during the three years prior to the date of the prospectus supplement.

We or any of the selling shareholders may sell the securities from time to time pursuant to underwritten public offerings, negotiated transactions, block trades or a combination of these methods or through underwriters or dealers, through agents and/or directly to one or more purchasers. The securities may be distributed from time to time in one or more transactions:

Each time that we or any of the selling shareholders sell securities covered by this prospectus, we will provide a prospectus supplement or supplements that will describe the method of distribution and set forth the terms and conditions of the offering of such securities, including (1) the name or names of any underwriters, dealers or agents and the amounts of securities underwritten or purchased by each of them; (2) if a fixed price offering, the public offering price of the securities and the proceeds to us and/or the selling shareholders; (3) any options under which underwriters may purchase additional securities; (4) any underwriting discounts or commissions or agency fees and other items constituting underwriters’ or agents’ compensation; (5) terms and conditions of the offering and (6) any discounts, commissions or concessions allowed or reallowed or paid to dealers.

Offers to purchase the securities being offered by this prospectus may be solicited directly. Agents may also be designated to solicit offers to purchase the securities from time to time. Any agent involved in the offer or sale of our securities will be identified in a prospectus supplement.

If a dealer is utilized in the sale of the securities being offered by this prospectus, the securities will be sold to the dealer, as principal. The dealer may then resell the securities to the public at varying prices to be determined by the dealer at the time of resale.

If an underwriter is utilized in the sale of the securities being offered by this prospectus, an underwriting agreement will be executed with the underwriter at the time of sale and the name of any underwriter will be provided in the prospectus supplement that the underwriter will use to make resales of the securities to the public. In connection with the sale of the securities, we, the selling shareholders, or the purchasers of securities for whom the underwriter may act as agent, may compensate the underwriter in the form of underwriting discounts or commissions. The underwriter may sell the securities to or through dealers, and those dealers may receive compensation in the form of discounts, concessions or commissions from the underwriters and/or commissions from the purchasers for which they may act as agent. Unless otherwise indicated in a prospectus supplement, an agent will be acting on a best efforts basis and a dealer will purchase securities as a principal, and may then resell the securities at varying prices to be determined by the dealer.

Any compensation paid to underwriters, dealers or agents in connection with the offering of the securities, and any discounts, concessions or commissions allowed by underwriters to participating dealers will be provided in the applicable prospectus supplement. Underwriters, dealers and agents participating in the distribution of the securities may be deemed to be underwriters within the meaning of the Securities Act, and any discounts and commissions received by them and any profit realized by them on resale of the securities may be deemed to be underwriting discounts and commissions. We and the selling shareholders may each or both enter into agreements to indemnify underwriters, dealers and agents against civil liabilities, including liabilities under the Securities Act, or to contribute to payments they may be required to make in respect thereof and to reimburse those persons for certain expenses.

Our common stock is listed on the NYSE. To facilitate the offering of securities, certain persons participating in the offering may engage in transactions that stabilize, maintain or otherwise affect the price of the securities. This may include over-allotments or short sales of the securities, which involve the sale by persons participating in the offering of more securities than were sold to them. In these circumstances, these persons would cover such over-allotments or short positions by making purchases in the open market or by exercising their over-allotment option, if any. In addition, these persons may stabilize or maintain the price of the securities by bidding for or purchasing securities in the open market or by imposing penalty bids, whereby selling concessions allowed to dealers participating in the offering may be reclaimed if securities sold by them are repurchased in connection with stabilization transactions. The effect of these transactions may be to stabilize or maintain the market price of the securities at a level above that which might otherwise prevail in the open market. These transactions may be discontinued at any time.

If indicated in the applicable prospectus supplement, underwriters or other persons acting as agents may be authorized to solicit offers by institutions or other suitable purchasers to purchase the securities at the public offering price set forth in the prospectus supplement, pursuant to delayed delivery contracts providing for payment and delivery on the date or dates stated in the prospectus supplement. These purchasers may include, among others, commercial and savings banks, insurance companies, pension funds, investment companies and educational and charitable institutions. Delayed delivery contracts will be subject to the condition that the purchase of the securities covered by the delayed delivery contracts will not at the time of delivery be prohibited under the laws of any jurisdiction in the United States to which the purchaser is subject. The underwriters and agents will not have any responsibility with respect to the validity or performance of these contracts.

The specific terms of any lock-up provisions in respect of any given offering will be described in the applicable prospectus supplement.

The underwriters, dealers and agents may engage in transactions with us, or perform services for us, in the ordinary course of business for which they receive compensation.

The following are descriptions of our capital stock and material provisions of our amended and restated articles of incorporation and amended and restated bylaws. These descriptions are summaries and are qualified by reference to our amended and restated articles of incorporation and amended and restated bylaws, as well as the Shareholders Agreement, which includes certain other provisions that materially impact the rights of our shareholders, including voting provisions.

Our authorized capital stock consists of 300,000,000 shares of common stock, par value $0.01 per share, and 1,000,000 shares of preferred stock, par value $0.01 per share, all of which preferred stock is undesignated. As of October 31, 2014, we had 127,852,205 shares of common stock outstanding and approximately 51 shareholders of record.

Holders of our common stock are entitled to one vote for each share held, and are entitled to vote together as a class, on all matters submitted to a vote of shareholders. Except for the election of directors, if a quorum is present, action on a matter is approved if the votes cast favoring the action exceed the votes cast against the action, unless the vote of a greater number is required by the North Carolina Business Corporation Act, or the NCBCA, our amended and restated articles of incorporation or our amended and restated bylaws. The election of directors is determined by a plurality of the votes cast in respect of the shares present in person or represented by proxy at the meeting and entitled to vote, meaning that the nominees with the greatest number of votes cast, even if less than a majority, will be elected. Our common shareholders do not have cumulative voting rights.

Under the NCBCA, a corporation may not make any distribution (including dividends, whether in cash or other property, and redemptions or repurchases of its shares) if the distribution would result in either (1) the corporation being unable to pay its debts when they become due or (2) the corporation’s assets being less than the sum of its liabilities plus any preferential liquidation rights of shareholders. For purposes of making this determination, the NCBCA permits a corporation’s board of directors to determine asset values based either on book values or on a fair valuation or other method that is reasonable in the circumstances. Holders of common stock are entitled to receive proportionately any dividends when and as declared by our board of directors, or our Board, subject to any preferential dividend rights of outstanding preferred stock, based on the number of shares of common stock then held of record by such holder.

In the event of our liquidation, dissolution or winding up, the holders of our common stock are entitled to receive proportionately all assets available for distribution to shareholders after the payment of all debts and other liabilities and subject to the prior rights of any outstanding preferred stock. Our outstanding shares are not subject to any redemption or sinking fund provisions, nor are they convertible into any other shares of our capital stock. The rights, preferences and privileges of holders of common stock are subject to and may be adversely affected by the rights of the holders of shares of any series of preferred stock that we may designate and issue in the future.

Our amended and restated articles of incorporation grant broad authority to our Board to determine the designations, preferences, relative rights and powers, including voting powers (or qualifications, limitations or restrictions thereof), of classes or series of such preferred stock without shareholder approval. Our authorized preferred stock is available for issuance from time to time in one or more series at the discretion of our Board without shareholder approval. Our Board has the authority to prescribe for each series of preferred stock (1) the number of shares in that series, (2) the consideration for such shares in that series and (3) the designations, preferences, relative rights and powers, including voting powers, full or limited, or no voting power, of the shares in that series, or the qualifications, limitations or restrictions of the shares in that series.

Anti-Takeover Effects of Our Shareholders Agreement and Articles of Incorporation and Bylaws

Our amended and restated articles of incorporation and amended and restated bylaws contain certain provisions that could have the effect of delaying, deferring or discouraging another party from acquiring control of our company. These provisions, which are summarized below, are expected to discourage coercive takeover practices and inadequate takeover bids. These provisions are also designed, in part, to encourage persons seeking to acquire control of our company to negotiate first with our Board. We believe that the benefits of increased protection of our potential ability to negotiate more favorable terms with an unfriendly or unsolicited acquirer outweigh the disadvantages of discouraging a proposal to acquire our company.

Our amended and restated articles of incorporation authorize the issuance of a significant number of shares of common stock and preferred stock. A large quantity of authorized but unissued shares may deter potential takeover attempts because of the ability of our Board to authorize the issuance of some or all of these shares to a friendly party, or to the public, which would make it more difficult for a potential acquirer to obtain control of our company. This possibility may encourage persons seeking to acquire control of our company to negotiate first with our Board.

Our authorized but unissued shares of preferred stock could also have anti-takeover effects. Under certain circumstances, any or all of the preferred stock could be used as a method of discouraging, delaying or preventing a change in control or management of our company. For example, our Board could designate and issue a series of preferred stock in an amount that sufficiently increases the number of outstanding shares to overcome a vote by the holders of common stock, or with rights and preferences that include special voting rights to veto a change in control. The preferred stock could also be used in connection with the issuance of a shareholder rights plan, sometimes referred to as a “poison pill.” Our Board is able to implement a shareholder rights plan without further action by our shareholders.

Use of our preferred stock in the foregoing manner could delay or frustrate a merger, tender offer or proxy contest, the removal of incumbent directors or the assumption of control by shareholders, even if these actions would be beneficial to our shareholders. In addition, the existence of authorized but unissued shares of preferred stock could discourage bids for our company even if such bid represents a premium over our then-existing trading price.

Our amended and restated articles of incorporation provide that shareholders may not act by written consent. As a result, any shareholder action is required to be taken at a duly called meeting of shareholders, which may make it more difficult for a potential acquirer to accomplish its objectives.

Requirements for Advance Notification of Shareholder Nominations and Proposals

Our amended and restated bylaws provide for advance notice procedures with respect to shareholder proposals and the nomination of candidates for election as directors, other than nominations made by or at the

direction of our Board or a committee of our Board or pursuant to the Shareholders Agreement. Pursuant to these provisions, to be timely, a shareholder’s notice must meet certain requirements with respect to its content and be received at our principal executive offices, addressed to the secretary of our company, within the following time periods:

These provisions may have the effect of precluding the conduct of certain business at a meeting if the proper procedures are not followed. These provisions may also discourage or deter a potential acquirer from conducting a solicitation of proxies to elect the acquirer’s own slate of directors or otherwise attempting to obtain control of our company.

Cumulative voting allows a shareholder to vote a portion or all of its shares for one or more candidates for seats on our Board. Without cumulative voting, a minority shareholder may not be able to gain as many seats on our Board as the shareholder would be able to gain if cumulative voting were permitted. The absence of cumulative voting makes it more difficult for a minority shareholder to gain a seat on our Board to influence our Board’s decision regarding a takeover. Under the NCBCA, by virtue of our date of incorporation and the fact that our amended and restated articles of incorporation do not give our shareholders the right to cumulate their votes, our shareholders are not entitled to cumulate their votes.

North Carolina has two primary anti-takeover statutes, the Shareholder Protection Act and the Control Share Acquisition Act, which govern the shareholder approval required for certain business combinations. As permitted by the NCBCA, we have opted out of both these provisions. Accordingly, we are not subject to any anti-takeover effects of the North Carolina Shareholder Protection Act or Control Share Acquisition Act. Our amended and restated articles of incorporation, however, incorporate a provision substantially identical to Section 203 of the Delaware General Corporation Law, an antitakeover law applicable to Delaware corporations. In general, this provision prohibits us from engaging in a business combination, such as a merger, with a person or group owning 15% or more of our voting stock for a period of three years following the date the person became an interested shareholder, unless (with certain exceptions) the business combination or the transaction in which the person became an interested shareholder is approved in a prescribed manner. In addition, our amended and restated articles of incorporation provide that the parties to the Shareholders Agreement will not be deemed to be “interested shareholders,” regardless of the percentage of our voting stock owned by them, and accordingly will not be subject to such restrictions.

Our amended and restated articles of incorporation, our amended and restated bylaws and the Shareholders Agreement contain provisions that establish specific procedures for nominating, electing and removing members of our Board, including the advance notice requirements discussed above under “—Requirements for Advance Notification of Shareholder Nominations and Proposals.” In addition, see “Certain Relationships and Related Person Transactions” and “Directors, Executive Officers and Corporate Governance—Composition and Qualifications of Our Board of Directors” in our 2013 Form 10-K for additional information regarding our Shareholders Agreement.

Subject to the Shareholders Agreement, vacancies and newly created directorships on our Board may be filled only by a majority of the directors then serving on the Board. The Shareholders Agreement provides that a vacancy created by the death, disability, retirement or removal of a director nominated pursuant to its terms may be filled only by the party to the Shareholders Agreement that nominated such director. Upon the request of the party that nominated a director, the parties to the Shareholder Agreement have agreed to vote for the removal of such director. Our amended and restated articles of incorporation provide that, except as otherwise provided in the Shareholders Agreement, once the parties to the Shareholders Agreement cease to collectively own a majority of our outstanding shares, directors may only be removed for cause and by the holders of 75% of our total outstanding stock.

As a practical matter, the nomination and voting requirements of the Shareholders Agreement make it exceedingly difficult for a potential acquirer to replace our directors through a proxy contest.

Additionally, our amended and restated articles of incorporation divide our Board into three classes, with staggered three-year terms. As a result, only one class of directors is elected at each annual meeting of shareholders, with the other classes continuing for the remainder of their respective three-year terms. The classification of our Board and provisions described above may have the effect of delaying or preventing changes in our control or management.

Our amended and restated bylaws may be altered, amended or repealed, or new bylaws may be adopted, by (1) a majority of the members of our Board or (2) the holders of a majority of our total outstanding shares entitled to vote, provided in the case of any special meeting of shareholders or directors, that the notice of such meeting must have stated that the amendment of our amended and restated bylaws was one of the purposes of the meeting. Our amended and restated bylaws may not be amended in any manner inconsistent with the Shareholders Agreement.

Once the parties to the Shareholders Agreement cease to collectively own a majority of our outstanding shares, our amended and restated bylaws may be altered, amended or repealed, or new bylaws may be adopted, by (1) a majority of the members of our Board or (2) the holders of 75% of our total outstanding shares entitled to vote, provided in the case of any special meeting of shareholders or directors, that the notice of such meeting must have stated that the amendment of our amended and restated bylaws was one of the purposes of the meeting. These provisions may have the effect of deferring, delaying or discouraging the removal of any anti-takeover defenses provided for in our amended and restated bylaws.

Except as provided under the NCBCA and as discussed below, amendments to our amended and restated articles of incorporation must be proposed by our Board and approved by holders of a majority of our total outstanding shares entitled to vote.

Once the parties to the Shareholders Agreement cease to collectively own a majority of our outstanding shares, shareholder amendments to certain provisions of our amended and restated articles of incorporation, such

as the classified board provision, require the approval of the holders of 75% of our total outstanding shares entitled to vote, provided in the case of any special meeting of shareholders, that the notice of such meeting must have stated that the amendment of our amended and restated articles of incorporation was one of the purposes of the meeting. These provisions may have the effect of deferring, delaying or discouraging the removal of any anti-takeover defenses provided for in our amended and restated articles of incorporation.

Our amended and restated articles of incorporation permit a special meeting of shareholders to be called by (1) a majority of the members of our Board; (2) the Chairman or Chief Executive Officer; or (3) for so long as the parties to the Shareholders Agreement collectively own a majority of our outstanding shares, by (a) any director nominated by Dr. Gillings, Bain Capital, TPG or 3i or (b) the holders of a majority of the outstanding shares of our common stock. These provisions may make a change in control of our business more difficult by delaying shareholder actions to elect directors until the next annual shareholder meeting.

Our amended and restated articles of incorporation provide that we renounce any interest or expectancy in the business opportunities of the Sponsors and their affiliates (other than our company and our subsidiaries) and all of their respective partners, principals, directors, officers, members, managers, managing directors and/or employees, and each such person will have no obligation to offer us those opportunities. This provision applies to a Sponsor (and affiliated parties) only for so long as a nominee to our Board designated by the Sponsor under the Shareholders Agreement continues to serve on the Board. Shareholders will be deemed to have notice of and consented to this provision of our amended and restated articles of incorporation.

Our amended and restated bylaws provide that, to the fullest extent provided by law, the sole and exclusive forum for all litigation relating to our internal affairs is required to be a state or federal court located within North Carolina, in all cases subject to the court’s having personal jurisdiction over the indispensable parties named as defendants. As a result, any action brought by any of our shareholders with respect to any such matters, including without limitation (1) any derivative action or proceeding brought on behalf of our company, (2) any action asserting a claim of breach of a fiduciary duty owed to us or any of our shareholders by any of our directors, officers or other employees, (3) any action asserting a claim arising pursuant to any provision of the NCBCA, our amended and restated articles of incorporation or our amended and restated bylaws or (4) any action asserting a claim governed by the internal affairs doctrine, will generally need to be filed in North Carolina and may not be filed in any other jurisdiction. In any such action where the NCBCA specifies the division or county wherein the action must be brought, the action must be brought in such division or county.

Sections 55-8-50 through 55-8-58 of the NCBCA permit a corporation to indemnify its directors, officers, employees or agents under either or both a statutory or nonstatutory scheme of indemnification. Under the statutory scheme, a corporation may, with certain exceptions, indemnify a director, officer, employee or agent of the corporation who was, is, or is threatened to be made, a party to any threatened, pending or completed legal action, suit or proceeding, whether civil, criminal, administrative or investigative, because of the fact that such person was a director, officer, agent or employee of the corporation, or is or was serving at the request of such corporation as a director, officer, employee or agent of another corporation or enterprise. This indemnity may include the obligation to pay any judgment, settlement, penalty, fine (including an excise tax assessed with respect to an employee benefit plan) and reasonable expenses incurred in connection with a proceeding (including counsel fees), but no such indemnification may be granted unless such director, officer, agent or employee (1) conducted himself in good faith, (2) reasonably believed (a) that any action taken in his official capacity with the corporation was in the best interests of the corporation or (b) that in all other cases his conduct

at least was not opposed to the corporation’s best interests, and (3) in the case of any criminal proceeding, had no reasonable cause to believe his conduct was unlawful. Whether a director, officer, employee or agent has met the requisite standard of conduct for the type of indemnification set forth above is determined by the board of directors, a committee of directors, special legal counsel or the shareholders in accordance with Section 55-8-55. A corporation may not indemnify a director, officer, employee or agent under the statutory scheme in connection with a proceeding by or in the right of the corporation in which the person was adjudged liable to the corporation or in connection with a proceeding in which a person was adjudged liable on the basis of having received an improper personal benefit.

In addition to, and separate and apart from the indemnification described above under the statutory scheme, Section 55-8-57 of the NCBCA permits a corporation to indemnify or agree to indemnify any of its directors, officers, employees or agents against liability and expenses (including attorney’s fees) in any proceeding (including proceedings brought by or on behalf of the corporation) arising out of their status as such or their activities in such capacities, except for any liabilities or expenses incurred on account of activities that were, at the time taken, known or believed by the person to be clearly in conflict with the best interests of the corporation.

Further, Sections 55-8-52 and 55-8-56 of the NCBCA require a corporation, unless its articles of incorporation provide otherwise, to indemnify a director or officer who has been wholly successful, on the merits or otherwise, in the defense of any proceeding to which such director or officer was a party. Unless prohibited by the articles of incorporation, a director or officer also may make application and obtain court-ordered indemnification if the court determines that such director or officer is fairly and reasonably entitled to such indemnification.

Finally, Section 55-8-57 of the NCBCA provides that a corporation may purchase and maintain insurance on behalf of an individual who is or was a director, officer, employee or agent of the corporation against certain liabilities incurred by such persons, whether or not the corporation is otherwise authorized by the NCBCA to indemnify such party.

As permitted by the NCBCA, our amended and restated articles of incorporation limit the personal liability of directors for monetary damages for breaches of duty as a director provided that such limitation will not apply to (1) acts or omissions not made in good faith that the director at the time of the breach knew or believed were in conflict with our best interests, (2) any liability for unlawful distributions under Section 55-8-33 of the NCBCA, (3) any transaction from which the director derived an improper personal benefit, or (4) acts or omissions occurring prior to the date the provision became effective. The term “improper personal benefit” does not include a director’s reasonable compensation or other reasonable incidental benefit for or on account of his or her services as one of our directors, officers, employees, independent contractors, attorneys or consultants. In the event that the NCBCA is amended to permit further limitation or elimination of the personal liability of a director, the personal liability of our directors will be limited or eliminated to the fullest extent permitted by the applicable law.

Our amended and restated bylaws require us to indemnify our directors and officers, and permit us to indemnify our employees and agents, to the fullest extent permitted under the NCBCA. Accordingly, we may indemnify our directors, officers, employees and agents in accordance with either the statutory or the non-statutory standards. From time to time, we may enter into indemnification agreements with certain of our directors, officers, employees and agents, and we have entered into indemnification agreements with certain of our directors. We also are required to advance certain expenses (including attorneys’ fees) to our directors and officers and permitted to advance expenses to our employees and agents. We currently maintain directors’ and officers’ insurance policies covering our directors and officers, as permitted in our amended and restated bylaws and required under our indemnification agreements.

We believe that our amended and restated articles of incorporation, amended and restated bylaws, indemnification agreements and insurance are necessary to attract and retain qualified persons to serve as directors and officers.

The limitation of liability and indemnification provisions in our amended and restated articles of incorporation, amended and restated bylaws, and indemnification agreements may discourage shareholders from bringing a lawsuit against directors for breach of their fiduciary duty. They may also reduce the likelihood of derivative litigation against directors and officers, even though an action, if successful, might benefit us and other shareholders. Furthermore, a shareholder’s investment may be adversely affected to the extent we pay the costs of settlement and damage awards against directors and officers as required or allowed by these indemnification provisions.

At present, we are not aware of any pending litigation or proceeding involving any of our directors or officers in which indemnification is required or permitted and we are not aware of any threatened litigation or proceeding that may result in a claim for indemnification.

The transfer agent and registrar for our common stock is American Stock Transfer & Trust Company, LLC. Its address is 6201 15th Avenue, Brooklyn, New York 11219, and its telephone number is (212) 936-5100.

The validity of the securities offered by this prospectus will be passed upon for us by Smith, Anderson, Blount, Dorsett, Mitchell & Jernigan, L.L.P.

The financial statements incorporated in this Prospectus by reference to the Annual Report on Form 10-K for the year ended December 31, 2013 have been so incorporated in reliance on the report of PricewaterhouseCoopers LLP, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting.

We have filed with the SEC a registration statement on Form S-3 under the Securities Act with respect to the shares of our common stock being offered by this prospectus. This prospectus, which constitutes part of the registration statement, does not contain all of the information contained in the registration statement and the exhibits to the registration statement. For further information with respect to us and our common stock, you should refer to the registration statement (including this prospectus) and the exhibits to the registration statement and the documents incorporated by reference in this prospectus. Statements contained in this prospectus about the contents of any contract or any other document are not necessarily complete, and in each instance, we refer you to the copy of the contract or other documents filed as an exhibit to the registration statement. Each of these statements is qualified in all respects by this reference.

We are subject to the informational requirements of the Exchange Act, and in accordance therewith, we file reports and other information with the SEC. You may read and copy the registration statement of which this prospectus is a part, such reports and other information at the SEC’s public reference room, which is located at 100 F Street, NE, Room 1580, Washington, D.C. 20549, on official business days during the hours of 10:00 a.m. to 3:00 p.m. You can request copies of these documents by writing to the SEC and paying a fee for the copying cost. Please call the SEC at 1-800-SEC-0330 for more information about the operation of the SEC’s public reference room. In addition, the SEC maintains an Internet website, which is located at http://www.sec.gov, that contains reports, proxy and information statements and other information regarding issuers that file electronically with the SEC. You may access the registration statement of which this prospectus is a part and the other reports and information that we have filed with the SEC at the SEC’s Internet website.

The SEC allows us to “incorporate by reference” information we file with it into our registration statement of which this prospectus is a part, which means that we can disclose important information to you by referring you to other documents. The information incorporated by reference is considered to be part of this prospectus, and information in documents that we file later with the SEC will automatically update and supersede information in this prospectus. We incorporate by reference into this prospectus the documents listed below and any future filings made by us with the SEC under Section 13(a), 13(c), 14 or 15(d) of the Exchange Act, except for information “furnished” under Items 2.02, 7.01 or 9.01 on Form 8-K or other information “furnished” to the SEC which is not deemed filed and not incorporated in this prospectus, until the termination of the offering of securities described in the applicable prospectus supplement. We hereby incorporate by reference the following documents:

We will provide to each person, including any beneficial owners, to whom a prospectus is delivered, upon written or oral request of any such person, a copy of the reports and documents that have been incorporated by reference into this prospectus, at no cost. Any such request should be directed to: Quintiles Transnational Holdings Inc., 4280 Emperor Blvd., Durham, North Carolina 27703, Attention: General Counsel, (919) 998-2000, officeofgeneralcounsel@quintiles.com. These documents are also available on the Investor Relations section of our website, which is located at http://www.quintiles.com, or as described under “Where You Can Find Additional Information” above. The reference to our website address does not constitute incorporation by reference of the information contained on our website.


	Per Share	Total
Public offering price	$	$
Underwriting discounts (1)	$	$
Proceeds to selling shareholders, before expenses	$	$


About This Prospectus Supplement			S-1
Cautionary Note Regarding Forward-Looking Statements			S-2
Market and Other Industry Data			S-3
Prospectus Supplement Summary			S-4
Risk Factors			S-6
Use of Proceeds			S-10
Capitalization			S-10
Selling Shareholders			S-11
Material United States Federal Income and Estate Tax Consequences to Non-United States Holders			S-14
Underwriting			S-18
Legal Matters			S-22
Experts			S-22
Where You Can Find More Information			S-22
Incorporation of Documents by Reference			S-23


	As of March 31, 2015 (unaudited)
	(dollars in thousands)
	Actual			As Adjusted
Cash and cash equivalents	$	779,068		$	720,511

Short-term debt:
Current portion of long-term debt, including capital leases	$	5,940		$	36,415

Long-term debt:
Long-term debt, less current portion, including capital leases⁽¹⁾	$	2,288,229		$	2,457,789

Total debt and capital lease obligations	$	2,294,169		$	2,494,204

Total shareholders’ deficit⁽²⁾		(612,307	)		(858,478	)

Total capitalization	$	1,681,862		$	1,635,726


	Shares Beneficially Owned Prior to This Offering					Number of Shares Being Offered		Shares Beneficially Owned After this Offering and the Concurrent Share Repurchase
Name and Address of Beneficial Owner	Number		Percent					Number		Percent
Parties to the Shareholders Agreement
Total shares held and offered by parties to the Shareholders Agreement(1)		51,622,962		41.3	%		10,572,471		42,050,491		%
Dennis B. Gillings, CBE, Ph.D. and affiliates(2)		16,027,183		12.7	%		3,220,020		12,807,163		%
Bain Capital and related funds(3)		15,629,782		12.5	%		3,140,177		12,489,605		%
TPG Funds(4)		11,207,612		9.0	%		2,251,719		8,955,893		%
Affiliates of 3i(5)		9,758,385		7.8	%		1,960,555		7,797,830		%

Temasek Life Sciences Private Limited(6)		6,383,856		5.1	%		1,282,579		5,101,277		%


Name	Number of Shares
Barclays Capital Inc.		5,927,525
Citigroup Global Markets Inc.		5,927,525
Total		11,855,050


About This Prospectus			1
Risk Factors			1
Forward-Looking Statements			2
The Company			3
Use of Proceeds			4
Selling Shareholders			4
Plan of Distribution			4
Description of Capital Stock			6
Legal Matters			13
Experts			13
Where You Can Find More Information			13
Incorporation by Reference			13



Barclays		Citigroup