The tight-knit Iranian-American Jewish community in Southern California is coming to terms with what could be its own mini-Madoff.

The Securities and Exchange Commission has charged John Farahi, a popular Persian-language radio host and financier, along with his wife and an employee, with defrauding $20 million from members of the Iranian-American community, using the funds to make risky financial bets and to build a luxurious mansion in Beverly Hills. While the amount of money that the Farahis are accused of taking is drawfed by Bernard L. Madoff’s multibillion-dollar Ponzi scheme, the case is bound to have major repercussions inside the established, and relatively affluent, Iranian-American diaspora.