Amazon CEO Jeff Bezos said Wednesday he can't guarantee employees have never used sales data from individual third-party sellers to develop the company's own products, despite a policy against that practice and past denials that Amazon engages in it.

Why it matters: Lawmakers and Amazon competitors and sellers have repeatedly hammered the e-commerce giant over accusations that Amazon accesses data on third-party sellers to boost its own house-label products. Bezos is admitting he can't rule out that this has happened.

Context: Democratic Rep. Pramila Jayapal, whose Seattle district is in Amazon's backyard, pressed Bezos on the issue during a House Judiciary antitrust panel hearing.

• Jayapal noted press reports that seem to contradict past testimony from Amazon associate general counsel Nate Sutton, who told her the company "does not use specific seller data" when creating its own private label products.

What they're saying: "I can't guarantee you that policy has never been violated," Bezos said, a striking admission that while Amazon does not allow this practice, it may be happening anyway. “I'm not yet satisfied we’ve gotten to the bottom of that."

Of note: Amazon has acknowledged that it does look at aggregate data on third-party sales in the course of developing its own products; its policy is only against singling out sellers.

• Under questioning from GOP Rep. Kelly Armstrong Wednesday, Bezos said that aggregate data can cover as few as two sellers, as opposed to strictly reflecting broad sales trends across product categories.

What's next: Bezos said Amazon would keep looking at this issue, and his admission ensures Amazon will continue to face major scrutiny over it.