FT. LAUDERDALE, Fla. (AP) _ Seventeen municipalities will share a $50 million settlement to recover about 70 percent of the investments they lost with the collapsed ESM Government Securities Inc.

U.S. District Judge Jose Gonzalez on Monday approved the out-of-court settlement between ESM's auditor, Grant Thornton, formerly called Alexander Grant & Co., and the investors.

After ESM failed in March 1985, owing some $300 million to dozens of creditors, investors sued Grant because its audited financial statements had shown ESM was a healthy company.

Jose L. Gomez, once a managing partner of Grant's South Florida offices, has pleaded guilty to accepting payments from ESM officials for approving false financial statements.

Testimony in the trial of two former high-ranking executives in the past several weeks disclosed massive fraud had kept the company afloat since the late 1970s.

The local governments could get their money this week, said David Levine, attorney for ESM court-appointed trustee Thomas Tew. Already, the municipalities have already received 20 cents on the dollar with funds salvaged by Tew from the assets of ESM and its officers.

Meanwhile, Tew said he would reduce his claims against Grant to the extent that they duplicate the settled claims.

''The settlement of this set of claims, which we believe to be the most significant ones asserted against us arising out of the ESM matter, insures that Grant's 450 partners will continue to serve tens of thousands of clients in 80 cities with confidence and dedication,'' said Burt Fischer, executive partner of Grant Thornton.

The only remaining litigation of substantial size is that relating to Home State Savings Bank in Ohio and American Savings and Loan Association in Florida, both controlled by Marvin Warner Sr. at the time they invested heavily with ESM.

The settlement approved Monday by the judge includes the city of Toledo, Ohio, which lost $19 million when ESM collapsed. The settlement means that Toledo, which benefited from an earlier distribution of ESM assets, will regain about 73 cents of every dollar it lost in the failure of ESM, which bought and sold government securities.

The state of Ohio, on behalf of the defunct Home State, has a $95 million claim against Alexander Grant & Co. through the ESM trustee, and the state has sued Alexander Grant for $157 million in Ohio. The Grant firm denies wrongdoing.

Home State's claims are separate from Monday's settlement and from a trial scheduled in October in Florida of remaining civil lawsuits against Alexander Grant & Co.

The Grant firm has filed counterclaims against Home State and American Savings and Loan Association. A personal lawsuit that Warner filed against the Grant firm in federal court in Florida has been dismissed.

Also Monday, Gonzalez approved a request by Tew to be paid for his work as court-appointed trustee in arranging a previous distribution of $35 million in ESM assets to creditors of the failed company. Tew requested fees of 3 percent of the settlement amount, the amount provided for by federal bankruptcy law, said Mark Raymond, one of Tew's associate lawyers.