UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 10-Q/A

(Amendment No. 1)

(Mark One)

For the quarterly period ended June 30, 2013

OR

For the transition period from                      to                     .

COMMISSION FILE NUMBER: 000-26489

ENCORE CAPITAL GROUP, INC.

(Exact name of registrant as specified in its charter)

(877) 445 - 4581

(Registrant’s telephone number, including area code)

(Not Applicable)

(Former name, former address and former fiscal year, if changed since last report)

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the last 90 days.    Yes  x    No  ¨

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).    Yes  x    No  ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act).    Yes  ¨    No  x

Indicate the number of shares outstanding of each of the issuer’s classes of common stock, as of the latest practicable date.

EXPLANATORY NOTE

Encore Capital Group, Inc. (the “Company”) is filing this Amendment No. 1 on Form 10-Q/A to amend our Quarterly Report on Form 10-Q for the quarter ended June 30, 2013 (the “Original Filing”), which we originally filed with the Securities and Exchange Commission (the “Commission”) on August 8, 2013. We are filing this amendment for the sole purpose of revising portions of Exhibit 10.24 to address comments we received from the Staff of the Commission in response to our confidential treatment request with respect to portions of Exhibit 10.24.

This amendment speaks as of the filing date of the Original Filing, does not reflect events occurring after the original filing date or modify or update those disclosures that may be affected by subsequent events, and no other changes are being made to any other disclosure contained in the Original Filing or any exhibits thereto.

As required by Rule 12b-15 under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), new certifications by the Company’s principal executive officer and principal financial officer are being filed herewith as exhibits to this Amendment pursuant to Rule 13a-14(a) of the Exchange Act. However, the Company is not including new certifications pursuant to Section 1350 of Chapter 63 of Title 18 of the United States Code (18 U.S.C. 1350) as no financial statements are being filed with this Amendment.

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SIGNATURES

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 thereunto duly authorized.

Date: December 20, 2013

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EXHIBIT INDEX

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