Beginning early in his chairmanship he focused the agency's enforcement efforts on stock option backdating, an illicit practice that had been exposed after the 2002 Sarbanes-Oxley Act changed the rules regarding the reporting of stock option grants. Under Cox the SEC investigated more than 160 stock option backdating cases, aided by the fact that the reporting forms for stock option disclosure were among the first to be mandated in “interactive data” format. Some of these cases were noteworthy for their size: in December 2007 the agency won $468 million in a settlement for stock option backdating against the former Chairman and CEO of UnitedHealth Group.