Too big to fail banks just keep getting bigger

Too big to fail? It may turn out that the biggest banks in the U.S. are too big to break up.

The idea that the TBTF institutions were going to get cut down to size after the financial crisis has turned into a giant myth. If anything, the system has gotten even bigger.

JPMorgan Chase, No. 1 among banks and thrifts in total assets, has seen its base swell to more than $2.5 trillion, according to SNL Financial. The company's deposit base alone has grown by 29 percent since the end of 2008.

That expansion has come amid repeated calls that the bank break up. Goldman Sachs analyst Richard Ramsden stated in an analysis for clients in January that dividing JPMorgan into two or four parts would "unlock value" for shareholders.

Read MoreIs the government trying to break up JPMorgan?

The so-called Big Four institutions—JPMorgan, Bank of America, Citigroup and Wells Fargo—continue to distance themselves from the pack, with some $8.2 trillion in total assets. That's 154 percent more than the rest of the top 50 banks combined.

There was little change in the rankings year over year, though Wells Fargo is closing in on Citi for the No. 3 spot. Citi contracted 2.6 percent from 2013 as the bank gets rid of noncore assets. Wells saw its assets surge 10.5 percent for the year.

Also, U.S. Bancorp moved into fifth place, ahead of Bank of New York Mellon.

A look at the biggest banks and their yearly gains: