Cohen v. Beneficial Industrial Loan Corp., 337 U.S. 541 (1949), was a case decided by the United States Supreme Court in the wake of the decision in Guaranty Trust Co. v. York that signified a high deference to state law in choice of law issues for federal courts sitting in diversity.

The estate's complaint asserted that since 1929 the managers and directors of Beneficial Industrial Loan Corp. had abused their positions to enrich themselves personally at the expense of the corporation.

In 1945, New Jersey passed a law that required shareholders who held less than 5% of the total shares and less than $50,000 to pay the legal bills of the defendant corporation if the suit was unsuccessful.

Because the issue at hand occurred in New Jersey, the corporation wanted Cohen's estate to post a $125,000 bond to ensure they would meet that potential burden.

The Federal Rules of Civil Procedure did not require such a bond, and the court held that the state law should be followed.