The chief executive of Whole Foods Market Inc. wrote anonymous online attacks against a smaller rival and questioned why anyone would buy its stock, before Whole Foods announced an offer to buy the other company this year.

The postings on Internet financial forums, made under the name "rahodeb," said Wild Oats Markets Inc. stock was overpriced. The statements predicted the company would fall into bankruptcy and then be sold after its stock fell below $5 per share.

In February, Whole Foods announced it would buy Wild Oats for about $565 million, or $18.50 per share.

The company acknowledged that the postings by "rahodeb" were written by CEO John Mackey.

They were made public this week as part of a lawsuit by the Federal Trade Commission to block Whole Foods from buying Wild Oats on antitrust grounds. Regulators say the sale would combine the two largest organic and natural foods retailers and raise prices for consumers by concentrating too much power in one company.