Bernie Sanders notched a progressive victory Tuesday by playing a role in securing a $15 minimum wage for all Amazon employees. Now the Vermont senator is turning his attention to another American powerhouse: the financial sector.

“Any financial institution that's too big to fail is too big to exist,” the Vermont senator said in a video announcing new legislation to take out JPMorgan Chase, Citigroup, Bank of America, and Wells Fargo. “It's time to break up the big banks. Today, I'm introducing legislation to do just that.”

Rep. Brad Sherman, a California Democrat, is co-sponsoring the bill. The legislation, if passed, would require the breakup of any company that has a total exposure that is beyond 3 percent of the U.S.’s GDP. It would split up six banks (JPMorgan, Bank of America, Citigroup, Wells Fargo, Goldman and Morgan Stanley) and four other companies (Berkshire Hathaway, Prudential Financial, MetLife and American International Group).

“I worry very much that in our nation today we are moving toward an oligarchic form of society where a small number of very wealthy individuals and large corporations have enormous control over our economic and political life,” Sanders said.

Sanders, an independent, and other prominent progressives on the left have criticized Democrats for their weak policy on financial institutions. Former President Barack Obama has long been criticized for going easy on big banks in the wake of the 2008 financial crisis. No big bank executives, for example, served jail time for their roles in the financial crisis.

Though the move is sure to rally Bernie’s base, it remains largely symbolic for now: Republicans control Congress, and President Donald Trump has shown little interest in going after big banks or the financial industry in general. In fact, he’s gone the other way, loosening regulations on financial institutions that were implemented following the 2008 crisis.

Rumor has it that Sanders, who currently ranks as the most popular U.S. senator, is mulling a 2020 presidential bid, after failing to secure the Democratic nomination in the 2016 primary against Hillary Clinton.