Mary Schapiro gave the U.S. Securities and Exchange Commission back its bark, brought in seasoned prosecutors to run regional offices and secured big money settlements from financial institutions responsible for the country’s recent financial troubles.

But critics said Schapiro, who announced her resignation as chairman of the agency on Monday, let the big fish off the hook, failing to build cases against executives of Wall Street firms and banks that played a role in triggering the biggest recession in U.S. history since the Great Depression.