Watch the Fight That Halted Trading on Wall Street

It takes a lot to stop trading on the floor of the New York Stock Exchange. On Tuesday, there wan't much action for about 23 minutes as traders were glued to their TV monitors.

The cause of the inaction? A heated CNBC TV debate, pitting IEX's Brad Katsuyama vs. BATS Global Markets president William O'Brien on high-speed trading and 'rigged' markets.

"You want to do this? Let's do this," Katsuyama said in response to O'Brien's prodding.

"I really do," O'Brien said.


And off they went, for more than 20 minutes. Traders stood transfixed as the two argued over the very nature of the stock market and whether the average investor could even compete with the big guys.

Katsuyama is at the heart of “Flash Boys,” the new book by financial writer Michael Lewis that chronicles the phenomenon of high-frequency trading. “HFT,” as Wall Street calls it, is essentially what happens when humans trading on the floor of stock exchanges are replaced by computers in data centers.

Some critics say that not only can the computers trade faster than humans — they can get information faster than humans too, giving the computers’ owners an unfair advantage over Main Street.

Watch more: Full 23-minute feud on CNBC

O'Brien pulled no punches in challenging Katsuyama and author Michael Lewis on their assertions that the market was unfair to ordinary investors.

"Shame on both of you for falsely accusing literally thousands of people and possibly scaring millions of investors in an effort to promote a business model," he said.

O'Brien challenged Katsuyama to repeat his claims from Lewis's book, and Katsuyama took the bait.

"I believe the markets are rigged and I also think you're part of the rigging," he said.

It wasn't just the NYSE floor, though, that was agape — "finance Twitter" also came to a standstill. For many, it was the most intense thing they'd seen on the news in years.

“This deserves another mention now that my jaw is off floor,” investor Paul Kedrosky said on Twitter, sharing a link to a video of the debate. staff and NBC News staff