Underdog Democratic presidential candidate former Maryland Gov. Martin O'Malley released a detailed plan outlining his plans to combat Wall Street corruption, as he tries to catch up with frontrunner Hillary Clinton and avowed socialist, Vermont Sen. Bernie Sanders.

The plan, the most in-depth of any proposed by a presidential candidate so far, calls for an end to "too big to fail" and structural reform of banks that benefited from the Wall Street bailout.

O'Malley says he would seek to reinstate the Glass-Steagall Act, which was repealed in 1999. Many liberals believe tearing down this wall between investment and consumer banking led to the 2008 financial crisis. Additionally, he would implement a three-year ban on regulators going to work for financial firms, double funding for the Securities and Exchange Commission and the Commodity Futures Trading Commission. O'Malley would also create an "economic crimes" division within the Justice Department.

O'Malley released an open letter to Wall Street's largest banks condemning their practices.

"If you — and your megabanks — which we, the American taxpayer, saved want to begin to restore the confidence in your leadership, you need to start by saying two things: 'we're sorry' and 'thank you,'" he wrote.

"The high-risk, reckless, and illegal activities of your megabanks were the primary cause of the 2008 crash, which caused the worst recession since The Great Depression, and cost the American economy an estimated $14 trillion to $22 trillion," O'Malley said in the letter.

Sanders has also supported reinstating Glass-Steagall but has yet to release as comprehensive of a plan as O'Malley.

Clinton is scheduled to release her economic plans beginning Monday. She has deep ties to Wall Street, but Sanders and O'Malley are expected to help push her to the left.