PHILADELPHIA – The California Public Employees’ Retirement System has voted its proxies against CVS Corp.’s plan to acquire pharmacy-benefits manager Caremark Rx Inc. for roughly $26 billion, according to the pension plan’s Web site.

The pension fund, also known as CalPERS, voted more than 2.1 million Caremark shares against the merger and more than 3.1 million CVS shares against the deal.

CVS shareholders approved the deal in a vote yesterday, while Caremark holders are scheduled to vote today.

Sacramento, Calif.-based CalPERS manages pension and health benefits for 1.5 million California public employees, retirees and their families. The pension fund has an investment portfolio valued at some $232.5 billion as of Jan. 31, and as such wields substantial power in corporate governance matters.