Scott I. London, a former senior partner with the accounting firm KPMG whose clients included Herbalife and Skechers USA, pleaded guilty on Monday before a federal judge in Los Angeles to a charge of securities fraud arising from his involvement in insider trading.

Mr. London, 50, who supervised more than 500 accounting professionals at KPMG, faces a maximum of 20 years in federal prison and a maximum fine of $5 million, according to the plea agreement.

Mr. London admitted that he gave the jeweler Bryan Shaw inside information regarding at least 14 separate earnings announcements or acquisitions by KPMG clients. The information included Herbalife’s earnings announcement on May 2, 2011, and an announcement by United Rentals on Dec. 16, 2011, on its acquisition of RSC Holdings, according to prosecutors.

Mr. London was accused of taking cash, concert tickets and jewelry, including a Rolex watch, from his onetime golfing buddy Mr. Shaw, who pleaded guilty earlier.