The big banks don't have to be split if the "right regulation" is in place, Sandy Weill, former chairman and CEO at Citigroup, told CNBC on Tuesday, a year after he shocked the financial world by calling for the breakup of the investment banking and commercial banking operations.
But Weill added in a "Squawk Box" interview that if regulations prevent investment banking from operating in a constructive way within big banks, then they should decide on their own to "split if they figure that's the best way that they can provide their services."
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He stressed that banks still don't know what the rules will be because regulations are not finalized, but he warned that the financial industry will be ineffective if new rules are too restrictive.
"A lot of the things we talked about [last time] have happened and even gotten worse. Like for example, the attack on anyone who's called a banker," Weill said.
Banks can't accomplish great things if they aren't allowed to make mistakes, he said.
Weill also told CNBC that he and his wife, Joan, are making an additional $100 million donation to Weill Cornell Medical College as a part of their $300 million fundraising effort.
One year ago in a "Squawk Box" interview, the so-called father of the supermarket bank said, "What we should probably do is go and split up investment banking from banking, have banks be deposit takers, have banks make commercial loans and real estate loans, have banks do something that's not going to risk the taxpayer dollars, that's not too big to fail."