Social Finance, a hot financial start-up, is the latest prominent Silicon Valley company to face accusations that it turned a blind eye to sexual harassment.

A former employee of Social Finance, better known as SoFi, said in a lawsuit filed Friday in a California state court that he had witnessed female employees being harassed by managers and was fired after he reported it.

The former employee who filed the suit, Brandon Charles, worked at SoFi for only a few months this year. But the lawyer handling the case, Robert Ottinger, said that he expected to file another lawsuit next week claiming broader mistreatment of other SoFi employees and seek class-action status.

“There appears to be a large groundswell of intense employee dissatisfaction at SoFi,” Mr. Ottinger said.