When Gutfreund was CEO of Salomon Brothers, a major scandal took place regarding the way Treasury bond trading was done by Salomon. Paul Mozer, head of the Government Bond desk at Salomon Brothers, was submitting bids in excess of what was allowed by the Treasury rules. When this was discovered and brought to the attention of Gutfreund, he did not immediately suspend Mr. Mozer. The exposure of Mr. Mozer's repeated violations of U.S. government bond auction rules resulted in a significant scandal during which regulators and some politicians called on the firm to be stripped of its Primary Dealer status. This action would have threatened the survival of the firm, then the largest participant in the U.S. government and mortgage bond trading markets. Warren Buffett, who through Berkshire Hathaway had recently acquired a $700 million preferred equity position in Salomon, became alarmed by the activities of the firm. Buffett actively took measures with Salomon in order to protect his investment, including briefly serving as CEO of Salomon Brothers. As a result of the scandal, Gutfreund and other senior managers of Salomon were forced to resign in 1991.