As the GOP finalized its Tax Cuts and Jobs Act late last year, it was already clear that the legislation would mean additional profits for major corporations, on top of their already impressive earnings in an economy that’s working—for them, at least. The nation’s largest banks are no exception. At JPMorgan Chase, for instance, start-of-year estimates pegged the company’s tax windfall at $4 billion a year, a boost that prompted the bank to up its philanthropic commitments by 40 percent.