The world’s biggest banks won a major victory on Friday when a judge dismissed a “substantial portion” of the claims in private lawsuits accusing them of rigging global benchmark interest rates.

Sixteen banks had faced claims totaling billions of dollars in the case, which had been considered their biggest legal threat aside from investigations being pursued by regulators in the United States and Europe into manipulation of the London Interbank Offered Rate, known as Libor. The list of banks includes Bank of America, Citigroup, Credit Suisse, Deutsche Bank, HSBC and JPMorgan Chase.

The banks had been accused by a diverse body of plaintiffs, as varied as bondholders and the City of Baltimore, of conspiring to manipulate Libor, a benchmark at the heart of more than $550 trillion in financial products.

But in the ruling on Friday, Judge Naomi Reice Buchwald of United States District Court in Manhattan, while acknowledging that her decision “might be unexpected,” granted the banks’ motion to dismiss federal antitrust claims and partly dismissed the plaintiffs’ claims of commodities manipulation. She also dismissed racketeering and state-law claims.