When Grassley asked whether it was the right decision in retrospect, Lew replied, “I’ll leave it for others to judge.”

Hatch returned to the issue in a second round of questioning, getting Lew to acknowledge that the bonus was on top of a $350,000 base salary at Citi and that it would have been clawed back for most employees who departed the following year. Lew’s contract had a clause that allowed him to still collect the large bonus if he left to take a top-level government job, which he did.

Asked what he did to earn the bonus, Lew said he managed the “business of the business,” selling off problem real estate and cutting costs.

“I think I actually performed quite well,” Lew said.

A budget director in the Clinton and Obama administrations, Lew’s experience dates back to being a top staffer for former House Speaker Thomas “Tip” O’Neill, D-Mass., in the 1980s. Lew reminded the committee that he was at the table for the 1986 revamp of the tax code, the last such tax deal, and oversaw three straight years of budget surpluses in the late 1990s.

On the idea of tax restructuring, Lew offered up what seemed to be several concessions to Republicans. He stated clearly that he doesn’t think a revamp of the corporate tax code should happen without similar changes to the individual tax code.

That’s important to the business community, because owners of smaller companies who declare their business incomes on their personal taxes fear that an overhaul of corporate taxes might leave them disadvantaged

Lew also said the nation didn’t “have the ability to lose revenue as we go through tax reform.” That signaled that he doesn’t favor lowering tax rates without getting rid of a wide number of tax loopholes enjoyed by individual and corporate filers.

Lew also noted that a revamp of the tax code “can be done in a revenue-neutral way.” That means it could be done without raising tax rates.

Sen. Maria Cantwell of Washington state, one of the few Democrats to pose tough questions to Lew, pushed him on whether the Clinton administration’s repeal of the Depression-era Glass-Steagall Act, which erected a wall between commercial and investment banking, was to blame for the U.S. financial crisis and thus should be restored.

The answer is complex, Lew said, adding that resuscitating a 1930s law may not be the best approach.

“I’ll take that as a no,” said Cantwell, cutting him off in midsentence.