An appellate panel on Tuesday affirmed a big victory for Barclays plc and its lawyers at Boies, Schiller & Flexner in long-simmering litigation over the collapse of Lehman Brothers, ruling that Barclays is entitled to billions in disputed Lehman assets.

The case stems from Barclays fire-sale purchase of Lehman’s brokerage business in 2008, when the now-defunct investment bank was overwhelmed by its exposure to the subprime mortgage market. Lehman Brothers’ estate alleged that Barclays had improperly secured a multibillion-dollar windfall in the deal, and the liquidation trustee for Lehman’s brokerage unit claimed that Barclays walked away with about $7 billion in assets that shouldn’t have been included in the sale.