The tax rate paid by private-equity managers on much of their income, less than half that for ordinary wage earners, is an “indefensible” tax break, the chief investment officer of the California Public Employees’ Retirement System said.

Calpers, as the pension fund is known, is one of the largest investors in private equity with about $50 billion as of June 30. The fund, the largest public pension in the U.S., has $234 billion of assets under management.

“General partners should recognize that tax treatment of their income has become indefensible,” said Joe Dear, the fund’s chief investment officer, at a meeting of Calpers’ board today in Sacramento.

Private-equity managers’ carried interest is taxed at the 15 percent rate for capital gains, rather than the 35 percent top rate that applies to regular income. U.S. public and private pensions provide 42 percent of the capital for all private- equity investments, according to the Private Equity Growth Capital Council in Washington.