After his warnings about Bernard Madoff’s Ponzi scheme went ignored for years, Harry Markopolos urged US regulators to encourage tipsters. Now, the forensic accountant and a team he put together are in position to benefit from those new incentives.

US government settlements with State Street and Bank of New York Mellon could produce a windfall for three former employees who blew the whistle on the banks' alleged mistreatment of foreign-currency-trading clients.