Operators of the Reserve Primary Fund were charged with fraud for allegedly failing to provide material information to investors about the fund's vulnerability as Lehman Brothers sought bankruptcy protection, the Securities and Exchange Commission said on Tuesday.

The SEC said that the Reserve Management Company, its chairman Bruce Bent Sr, its vice chairman and president Bruce Bent II and Resrv Partners failed to provide key information to investors, the fund's board of trustees, and rating agencies as Lehman filed for bankruptcy protection on September 15.

(Reporting by Rachelle Younglai)