UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d)

OF THE SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported) January 6, 2014

PACER INTERNATIONAL, INC.

(Exact name of registrant as specified in its charter)

Commission file number 000-49828

6805 Perimeter Drive

Dublin, OH 43016

Telephone Number (614) 923-1400

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

On January 5, 2014, Pacer International, Inc., a Tennessee corporation (“Pacer”), entered into a definitive Agreement and Plan of Merger (the “Merger Agreement”) with XPO Logistics, Inc., a Delaware corporation (“XPO”), and Acquisition Sub, Inc., a Tennessee corporation and an indirect wholly-owned subsidiary of Parent, providing for the acquisition of Pacer by XPO.

On January 6, 2014, Pacer and XPO issued a joint press release announcing the execution of the Merger Agreement. The full text of the press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated herein by reference.

On January 6, 2014, XPO and Pacer intend to host a joint investor conference call regarding the proposed merger with analysts and investors. The slides and accompanying script to be used in connection with this conference call are furnished as Exhibits 99.2 and 99.3, respectively, to this Current Report on Form 8-K and are incorporated herein by reference.

The information required by Item 1.01, including a copy of the Merger Agreement, will be filed in a separate Current Report on Form 8-K.

Item 9.01 Financial Statements and Exhibits.

Additional Information

In connection with the merger, XPO will file with the U.S. Securities and Exchange Commission (the “SEC”) a Registration Statement on Form S-4 that will include a Proxy Statement of Pacer and a Prospectus of XPO, as well as other relevant documents concerning the proposed transaction. XPO AND PACER SHAREHOLDERS ARE URGED TO READ THE PROXY STATEMENT / PROSPECTUS REGARDING THE MERGER WHEN IT BECOMES AVAILABLE AND ANY OTHER RELEVANT DOCUMENTS FILED WITH THE SEC, AS WELL AS ANY AMENDMENTS OR SUPPLEMENTS TO THOSE DOCUMENTS, BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT THE MERGER, PACER AND XPO. Investors and shareholders may obtain copies of these documents (when they are available) and other documents filed with the SEC at the SEC’s web site at www.sec.gov. Investors and shareholders may also obtain, free of charge, copies of these documents filed with the SEC by XPO through the investor relations page on XPO’s corporate website at www.xpocorporate.com or by contacting XPO Logistics, Inc. at Five Greenwich Office Park, Greenwich, CT 06831, Attention: Investor Relations. In addition, investors and shareholders may also obtain, free of charge, copies of these documents filed with the SEC by Pacer through the investor relations page on Pacer’s corporate website at www.pacer.com or by contacting Pacer International, Inc. at 6805 Perimeter Drive Dublin, OH 43016, Attention: Investor Relations.

Participants in Solicitation

XPO, Pacer and their respective executive officers and directors may be deemed to be participants in the solicitation of proxies from Pacer shareholders with respect to the proposed merger. Information about XPO’s executive officers and directors is available in XPO’s proxy statement on Schedule 14A for its 2013 annual meeting of shareholders, filed with the SEC on April 27, 2013. Information about (1) Pacer’s executive officers and directors is set forth in Pacer’s Annual Report on Form 10-K filed with the SEC on February 8, 2013 and (2) their ownership of the Pacer shares is set forth in Pacer’s proxy statement on Schedule 14A filed with the SEC on March 13, 2013. Investors and shareholders may obtain more detailed information regarding the direct and indirect interests of XPO, Pacer and their respective executive officers and directors in the proposed Merger by reading Proxy Statement/Prospectus regarding the Merger when it becomes available. Copies of these documents may be obtained, free of charge, as described above. This document shall not constitute an offer to sell or the solicitation of an offer to sell or the solicitation of an offer to buy any securities, nor shall there be any sale of securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. No offer of securities shall be made except by means of a prospectus meeting the requirements of Section 10 of the Securities Act of 1933, as amended.

Forward Looking Statements

This Report on Form 8-K includes forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. All statements other than statements of historical fact are, or may be deemed to be, forward-looking statements. In some cases, forward-looking statements can be identified by the use of forward-looking terms such as “anticipate,” “estimate,” “believe,” “continue,” “could,” “intend,” “may,” “plan,” “potential,” “predict,” “should,” “will,” “expect,” “objective,” “projection,” “forecast,” “goal,” “guidance,” “outlook,” “effort,” “target” or the negative of these terms or other comparable terms. However, the absence of these words does not mean that the statements are not forward-looking. These forward-looking statements are based on certain assumptions and analyses made by us in light of our experience and our perception of historical trends, current conditions and expected future developments, as well as other factors we believe are appropriate in the circumstances.

These forward-looking statements are subject to known and unknown risks, uncertainties and assumptions that may cause actual results, levels of activity, performance or achievements to be materially different from any future results, levels of activity, performance or achievements expressed or implied by such forward-looking statements. Factors that might cause or contribute to a material difference include, but are not limited to, those discussed in XPO’s and Pacer’s filings with the SEC and the following: economic conditions generally; competition; XPO’s ability to find suitable acquisition candidates and execute its acquisition strategy; the expected impact of the acquisition of Pacer, including the expected impact on XPO’s results of operations; the ability to obtain the requisite regulatory approvals, Pacer shareholder approval and the

satisfaction of other conditions to consummation of the transaction; the ability to realize anticipated synergies and cost savings; XPO’s ability to raise debt and equity capital; XPO’s ability to attract and retain key employees to execute its growth strategy, including retention of Pacer’s management team; litigation, including litigation related to misclassification of independent contractors; the ability to develop and implement a suitable information technology system; the ability to maintain positive relationships with XPO’s network of third-party transportation providers; the ability to retain XPO’s and Pacer’s largest customers; XPO’s ability to successfully integrate Pacer and other acquired businesses; and governmental regulation. All forward-looking statements set forth in this document are qualified by these cautionary statements and there can be no assurance that the actual results or developments anticipated will be realized or, even if substantially realized, that they will have the expected consequences to, or effects on, XPO, Pacer or their respective businesses or operations. Forward-looking statements set forth in this document speak only as of the date hereof, and neither XPO nor Pacer undertake any obligation to update forward-looking statements to reflect subsequent events or circumstances, changes in expectations or the occurrence of unanticipated events except to the extent required by law.

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

INDEX TO EXHIBITS