Whole Foods Market, Inc., yesterday asked competitors in 29 markets to provide pricing and other confidential information to help it defend its merger with Wild Oats against a challenge from the Federal Trade Commission, according to a published report.

In letters to the rival food retailers, c.e.o. John Mackey promised the documents would be reviewed only by attorneys working on the case, according to e.v.p. John Sud. Some competitors said they would provide the information while others refused to comply, Sud noted during a conference call yesterday. He declined to name the companies that were contacted, Bloomberg reported.

Austin, Texas-based Whole Foods completed its $565 million acquisition of Wild Oats in 2007 after the FTC was unable to block the deal over concerns the merger would be detrimental to consumers by driving up prices and reducing competition. The company has since sold 35 of the 110 stores it acquired, closed others, and rebranded most of the rest, according to Sud.

After a successful appeal in July, the agency reopened its antitrust review of the merger. A trial before an FTC administrative law judge is scheduled for April 6.

The FTC told a federal judge this week that Whole Foods, which now has 270 stores, should be ordered to rebrand former Wild Oats stores and keep them as a distinct unit until the review is completed.