SACRAMENTO, California (Reuters) - Calpers, the $133 billion pension fund, on Friday urged the top 100 shareholders of Bermuda-based Tyco International Ltd. to vote against keeping the conglomerate's corporate address in Bermuda.

In a letter to Tyco's top 100 shareowners, the fund, or California Public Employees' Retirement System, urged them to vote at the company's March 6 annual meeting for a corporate move back to the United States.

Tyco's senior executives operate from offices in New York City, and its US headquarters is in Exeter, New Hampshire. But the company uses an address in Bermuda for tax advantages. Tyco made the move under former chairman Dennis Kozlowski in 1997. Tyco's board, which is getting a fresh slate of directors, has recommended shareholders vote against leaving Bermuda, as proposed in a shareholder resolution by the American Federation of State County & Municipal Employees. Calpers said the board has agreed to study the issue after the annual meeting. Tyco declined to comment on the Calpers letter.

Calpers owns 1.4 million shares of Tyco, whose stock fell about 71 percent last year amid charges that former senior executives looted the company to a tune of $600 million.

"Offshore incorporations weaken shareholder protections and severely limit shareowners' abilities to pursue their rightful legal remedies if necessary," said Fred Buenrostro, chief executive of Calpers. Tyco shares slipped 7 cents to $14.90 in afternoon trade on the New York Stock Exchange. The stock is down nearly 13 percent this year, underperforming the 3 decline on the Standard & Poor's 500 Index.