Ohio Democratic Sen. Sherrod Brown has kept a relatively low-profile since his election to the Senate in 2006. But behind-the-scenes, he has built up a reputation as biggest bank-buster in the Democratic Party, superseding even Massachusetts’ Sen. Elizabeth Warren as the top bogeyman for financial industry lobbyists.

Since the passage of the Dodd-Frank financial reform bill, Brown has become the leading voice in the Senate calling for breaking up big banks, introducing legislation in the last Congress that would have ensured that no bank held more than 10 percent of total insured deposits and capped non-deposit liabilities at 2 percent of GDP.