Calpers, the biggest U.S. public pension fund, said on Thursday it is seeking shareowner support for its proposal to require a majority vote to elect unopposed candidates to the board of Apple Inc.

We believe a majority voting standard is necessary to provide shareowners better protection for the long-term -- accountability is our best protection in the face of uncertainty, said Anne Simpson, head of corporate governance at Calpers, the $226 billion California Public Employees' Retirement System.

(Editing by Robert MacMillan)