"This hopefully is a signal that the role of economic analysis within the agency is being enhanced, and I think that's a welcome development," Overdahl, who is now a vice president at NERA Economic Consulting in Washington, said in an interview with Bloomberg. He called Lewis an "outstanding economist."

Overdahl said the SEC has faced repeated court challenges over the cost analyses of rules. "Getting the economics right is very important to the agency," he said.

In addition to teaching and publishing research on market volatility and analyst herd behavior, he also is an expert in futures kets, margin adequacy, corporate earnings management, corporate financial policy, executive compensation and selective disclosure.