In testimony before a U.S. Senate antitrust panel in September 2011, Jeffrey Katz, the chief executive of NexTag, said that Google's business interests conflict with its engineering commitment to an open-for-all Internet and that: "Google doesn't play fair. Google rigs its results, biasing in favor of Google Shopping and against competitors like us." Jeremy Stoppelman, the chief of Yelp, said sites like his have to cooperate with Google because it is the gateway to so many users and "Google then gives its own product preferential treatment." In earlier testimony at the same hearing Eric Schmidt, Google's chairman, said that Google does not "cook the books" to favor its own products and services.