Calpers, the biggest U.S. pension fund and one of the nation’s best known corporate governance activists, said on Thursday it would withhold votes for Apple’s entire board of directors after it failed to implement a shareholder-approved proposal to treat stock options as an expense. The California Public Employees’ Retirement System also criticized Apple’s board for authorizing Apple’s auditor, KPMG LLP, to perform nonauditing, or consulting services, according to Reuters.