The largest U.S. banks, after a decade of efforts at simplifying their organizational structure, still have hundreds of overseas subsidiaries and a fondness for tax-haven or secrecy-protecting locations such as the Cayman Islands.

Those are the findings of a study by the Federal Reserve Bank of New York published on Monday, comparing the subsidiaries of the 50 largest banks in 2007 and 2017. While the maximum number of units owned by one firm has halved to 1,335 in that decade, one lender still has units spanning 31 different industries, little changed from before the crisis, the New York Fed study said.

Regulators have been pushing the largest firms to simplify their legal entity structures since the 2008 crisis, as part of efforts to make them easier to wind down in case of failure.Lehman Brothers Holdings Inc.’s bankruptcy has still not concluded after almost 10 years as thousands of subsidiaries around the world, many with dealings with each other, complicated its resolution.

Tax havens or financial secrecy locations are home to about a quarter of bank units based in advanced economies and half of those based in emerging markets, the study said.Ireland’s share in all foreign subsidiaries has increased to 5 percent from 3 percent a decade ago. Ireland’s 12.5 percent corporate tax rate is among the lowest in the world. The share of the Cayman Islands, which has no corporate tax, has risen to 11 percent from 10 percent.