Fremont General has agreed to buy Malibu Savings.

The Santa Monica-based insurance company said it will acquire the savings and loan for about $17 million in cash from U.S. Shelter Corp., a real estate syndication firm in Greenville, S.C. The S&L;, formed four years ago, has $125 million in assets and offices in Malibu, Fountain Valley and Temecula. The agreement is subject to regulatory approval and is expected to be completed in late 1986 or early 1987.