MetLife has won a major legal challenge to the government’s policy for preventing another financial crisis, as a federal judge tossed out its designation by regulators that its failure would pose a threat to the financial system.

MetLife Inc., the largest U.S. insurance company by assets, took the government to court more than a year ago to appeal its labeling by the Financial Stability Oversight Council as “systemically important” and requiring stricter supervision. That meant regulators deemed MetLife to be so big and entwined with the financial system that it could threaten the economy if it collapsed.