One of the giant mortgage companies at the heart of the credit crisis paid $15,000 a month from the end of 2005 through last month to a firm owned by Senator John McCain’s campaign manager, according to two people with direct knowledge of the arrangement.

The disclosure undercuts a remark by Mr. McCain on Sunday night that the campaign manager, Rick Davis, had had no involvement with the company for the last several years…

Jill Hazelbaker, a spokeswoman for the McCain campaign, did not dispute the payments to Mr. Davis’s firm. But she said that Mr. Davis had stopped taking a salary from the firm by the end of 2006 and that his work did not affect Mr. McCain.

“Senator McCain’s positions on policy matters are based upon what he believes to be in the public interest,” Ms. Hazelbaker said in a written statement.