Whole Foods Munches Estimates

At the hearing Tuesday, Whole Foods argued that the FTC has not considered relevant economic data such as price changes at its stores after Wild Oats exited markets where the two competed, according to the Associated Press.

The FTC countered that the pricing data is inadequate. It further argued that in some instances, enough time has not passed to determine whether the store closures affected Whole Foods' prices, the AP reported.

A ruling on the case is expected in mid-August.

Whole Foods has been under fire in recent weeks after it was revealed that Mackey had been boosting his company's profile by posting comments on Yahoo! Finance message boards under the pseudonym "Rahodeb" over a seven-year period. He also used the forum to criticize Wild Oats.

The Securities and Exchange Commission has begun an inquiry into the matter. Mackey has issued an apology to shareholder for the "error in judgment."

On Thursday, Mackey acknowledged the negative publicity from the case, but noted that it hasn't hurt sales.

"We're hopeful that the Wild Oats merger will go through -- that'll be good PR," he said.