Trading Suspension Highlights New York Stock Exchange's Shrinking Influence

This is a partial transcript from Prof. Robert Battalio's interview with NPR. Listen to the story and read the entire transcript on the NPR website.

The New York Stock Exchange opened normally Thursday, after computer problems forced the exchange to shut down for much of the day on Wednesday.

KELLY MCEVERS, HOST: Things were back to normal at the New York Stock Exchange today. Yesterday, a faulty software upgrade forced the nation's oldest stock exchange to suspend trading for nearly four hours. The explanation is that a technical glitch made it hard for the trading software to communicate with other systems, so orders couldn't be processed. The incident is a big embarrassment even though it didn't cause much of a problem for most investors. NPR's Jim Zarroli reports.

JIM ZARROLI, BYLINE: In the eyes of most people, the floor of the New York Stock Exchange is synonymous with the stock market, and so much about the exchange, from the busy trading pits to the closing bell, have become fixtures of American life. But the NYSE has changed dramatically in just the past 10 years, and it's likely to keep changing, says Robert Battalio, professor of finance at Notre Dame.

ROBERT BATTALIO: At least for my generation, it symbolizes capitalism and all, right? But I think, you know, in 20, 30 years, it's not going to have the same meaning, is my guess.

ZARROLI: The past few years have seen a proliferation of new electronic markets that compete with the NYSE, and federal regulations require each trade to be executed on the market that provides the best price. JJ Kinahan is chief market strategist at TD Ameritrade.

JJ KINAHAN: If you look at 20 years ago where the only place to really trade was the New York Stock Exchange, there are multiple venues now to go to with your orders. So there may be a better bid or a better offer at another venue.

ZARROLI: The spread of these new trading venues has made the market a lot more complex, but Kinahan says it's also made stock trading less vulnerable to technical problems.

KINAHAN: And I think people lose sight of this. If you think about 20 years ago, if the phone system went down, trading would have stopped 'cause there was only one venue.

ZARROLI: Today, when one market experiences a glitch, trades can quickly be routed to competing exchanges, says Robert Battalio.

BATTALIO: The idea was, if one goes down, that market just pulls away, and trading continues, which is kind of what you saw yesterday.