The completion of US banking “stress tests” has unleashed a fee bonanza for Wall Street, with financial institutions set to earn more than $500m in just a few weeks for helping rivals raise equity to plug capital shortfalls and repay federal aid.

Bankers expect a bumper period for equity fund-raisings as many of the 19 lenders involved in the tests tap the market to fill the capital holes uncovered by regulators or pay back funds from the Troubled Asset Relief Programme (Tarp).