Sanford I. Weill speaks at a news conference March 20, 2002, in Tokyo, Japan. Weill, who engineered Citigroup and the creation of megabanks, says big banks should be split up. Will the debate now gain traction? - 

Stacey Vanek Smith: Sanford Weill was once a big name on Wall Street -- and the king of making big banks bigger. Back in 1998, he combined Travelers, the insurance company, with Citibank to create Citigroup. But now Weill wants to break up big banks.

Marketplace's Heidi Moore has that story.

Heidi Moore: Sandy Weill was the man who had the vision for the modern megabank. He was like the Dr. Frankenstein of banking.

"Frankenstein": It's alive, it's alive!

Back then, the megabank looked like a great advancement. But as banks got bigger, and bigger, and then too big to fail, they helped cause the worldwide financial crisis. So, after 2008, the megabank monster was being chased by torch-wielding mobs.

John Reed, who created Citigroup with Weill, expressed regret over the idea of megabanks on TV a few months ago.

John Reed: It turns out to have been something that -- the word 'disaster' is maybe strong enough.

That's a sentiment shared by another former big-bank CEO, the former chair of the FDIC, and the president of the Dallas Federal Reserve.

Dennis Kelleher: His progeny -- I don't know what you want to call it -- his creation did not turn out the way that he had hoped.

That's Dennis Kelleher, the CEO of advocacy group Better Markets. He hopes that Weill's change of heart influences other bankers.

Kelleher: My first thought was: game changer. Instead of the arrogance and whining and entitlement these people have shown, they might want to start reflecting.

When a village elder like Weill speaks, perhaps Wall Street will listen.

In New York, I'm Heidi Moore for Marketplace.

Follow Heidi N. Moore at @moorehn