NEW YORK (Reuters) - A U.S. judge has dismissed a lawsuit by Chevron Corp <CVX.N> workers who said the oil company breached its fiduciary duties by putting costly and poorly performing investment options in a $19 billion employee savings plan.

In a decision on Monday, Chief Judge Phyllis Hamilton of the U.S. District Court in Oakland, California, wrote that the workers failed to raise a "plausible inference" of wrongdoing.

Hamilton gave the plaintiffs until Sept. 30 to file an amended complaint.

"The mere fact that the fund's price dropped is not sufficient to state a claim for breach of fiduciary duty," she wrote.

The judge also said it was acceptable for the plan to offer a money market fund rather than a higher-return stable value fund for plan participants seeking to preserve capital.

Neither Jerome Schlichter, whose firm represents the plaintiffs, nor a spokesman for San Ramon, California-based Chevron immediately commented.

Schlichter's St. Louis firm has pursued many lawsuits accusing companies of mismanaging 401(k) and other retirement plans. This month it also brought similar claims against a number of major universities.

The case is White et al v. Chevron Corp et al, U.S. District Court, Northern District of California, No. 16-00793.

(Reporting by Ross Kerber; Editing by Lisa Von Ahn)