In a surprising change of heart, the ex-CEO of Citigroup, Sandy Weill, backed off his former position that there is nothing wrong with Big Banks.

Politico reports:

Weill, the aggressive deal maker who built Citigroup on the idea that in banking, bigger is better, said Wednesday that he believes big banks should be broken up.

Speaking on CNBC's "Squawk Box," the 79-year-old Weill appeared to shock the show's anchors when he said that consumer banking units should be split from riskier investment banking units. That would mean dismembering Citigroup as well as other big U.S. banks, like JPMorgan Chase and Bank of America.

Contrary to Weill’s record at Citigroup (he built the bank into a mammoth operation), Weill’s turnaround is at odds with other banking giants such as JPMorgan, whose CEO Jamie Dimon regularly lobbies Congress and regulators to allow the Big Banks to continue business as usual.

Big Banks were major players in the financial crisis of 2008. Risky speculation led to the housing bubble and overall economic collapse that devastated working families. And, as we saw in 2008, when the too-big-to-fail banks make too many losing bets, the U.S. taxpayers end up footing the bill.

When asked why he changed his mind, Weill responded:

I think the world changes…and the world that we live in is different than the one that we lived in 10 years ago.