The Securities and Exchange Commission on Tuesday accused the father-and-son team that operated the Reserve Primary Fund of securities fraud, contending they had lied to investors when the fund “broke the buck” last fall and created a near panic in the money market fund industry.

Bruce Bent Sr. and his son, Bruce Bent II, were charged in a civil lawsuit with “falsely assuring” shareholders, the fund’s board and rating agencies that their flagship fund remained safe and liquid at a time when the bankruptcy of Lehman Brothers had made the fund far more precarious than investors realized.

The Bents “engaged in a systematic campaign to deceive the investing public,” the S.E.C. said in the lawsuit, which was filed in Federal District Court in Manhattan. The government also said that the two men had “placed their own financial and reputation interests ahead of the fund and its shareholders.”

The $62 billion Reserve Primary Fund, founded in 1970, was the nation’s first and one of the largest money market funds. The senior Mr. Bent, who helped invent the money fund concept, was described by the S.E.C. as “the public face” and “a longtime advocate of the safety and stability of money market funds.”