Millions of credit cardholders are receiving an unexpected holiday surprise: an $18 check.

The check is a refund from the Currency Conversion Fee Antitrust Settlement, a class-action lawsuit that was filed against credit card companies, accusing them of improperly disclosing fees for credit and debit transactions made abroad.

The suit was filed several years ago and more than 10 million Visa, MasterCard, and Diners Club cardholders who used their cards abroad filed claims forms. The Court granted final approval of the settlement in a Memorandum and Order dated October 22, 2009, and all of the appeals have now concluded. On October 5, 2011 the Court entered an Order authorizing the Settlement Administrator to disburse the available settlement funds.

Most checks are for $18.04, but if you traveled extensively, your check may be larger.

If you have questions, or if you have moved since you filed the claim and want to verify the address, you can visit the settlement website at https://ccfsettlement.com/contact/, or write them at:

Foreign Currency Antitrust Litigation
Settlement Administrator
P.O. Box 290
Philadelphia, PA 19105-0290.

The Better Business Bureau cautions against copycat scams and advises consumers to verify any check that may look unusual or suspicious.

A separate settlement involving American Express is pending.