Nearly five years after Lehman Brothers Holdings Inc. filed for bankruptcy, managers of the bank’s estate are demanding millions of dollars from nonprofits.

Once the world’s fourth-largest investment bank, Lehman filed the biggest bankruptcy in U.S. history on Sept. 15, 2008, after suffering billions in losses on subprime mortgages. It had more than 1.7 million derivative trades with thousands of banks, hedge funds, companies, municipalities and sovereign nations when it filed for protection from creditors.