DAVID GREENE, HOST:
Now let's hear about a new tool that may give investors out there the leg up they're looking for in the stock market. It is called sentiment analysis. It's a still developing field of research that harnesses social media and news sites to predict how stocks will perform.
That may sound far-fetched, but WNYC's Ilya Marritz reports that the idea is beginning to gain some acceptance.
ILYA MARRITZ, BYLINE: High school was not a particularly awesome time in the life of Arthur J. O'Connor. That social fairy dust that some people seem to have, he didn't have it.
ARTHUR O'CONNOR: I was a wallflower. I was a nerd. I was incredibly intimidated by everybody.
MARRITZ: Well, whatever he lacked in cool, O'Connor had in brains. He went on to work a couple decades on Wall Street in risk management, and then enrolled in a PhD business program, where he's written a paper that's gotten quite a bit of attention. The title...
O'CONNOR: "The Power of Popularity: An Empirical Study of Fan Counts and Consumer Brand Stock Prices."
MARRITZ: The Power of Popularity. By the way, we're in a cafe just downstairs from O'Connor's day job, in midtown.
O'CONNOR: My theory was, you know, it's like in high school. Does being really popular help you win friends, help you enhance your performance? And it turns out that yeah, popularity does seem to help brands.
MARRITZ: To test this, O'Connor tracked 30 brands with the most followers on Facebook.
O'CONNOR: So it would be Abercrombie and Fitch, Adidas, Aeropostale, American Eagle Outfitters, Best Buy...
MARRITZ: He followed those companies' "likes" on Facebook for a whole year, while also tracking their daily share price. And what O'Connor found astonished him.
O'CONNOR: So 99.95 percent of the change could be explained by the change in fan counts.
MARRITZ: You're saying that most of the change in a company's stock price - the overwhelming majority of it - correlates to the Facebook "likes" that day or in that period.
O'CONNOR: Yes, that's correct - that's correct.
MARRITZ: That's insane.
O'CONNOR: Yes, it is. But it's true.
MARRITZ: It's not that Facebook "likes" caused shares to rise or fall, but the admiration a company gets on social media seems to be a good clue about stock market performance. Naturally, people on Wall Street are interested. And many of them are already buying so-called sentiment feeds and folding them into the algorithms they use to buy and sell stocks. Kind of like a digital mood ring.
Rich Brown is head of financial analytics at Thomson Reuters, one of the largest providers of sentiment analysis.
RICH BROWN: Typically, our clients are hedge funds and institutional money managers that would look at interpreting this data in different strategies.
MARRITZ: From his window above Times Square, Brown can see across the Hudson River to New Jersey, where Thomson Reuters' supercomputers regularly scan four and a half million news and social media sites
(SOUNDBITE OF TYPING)
MARRITZ: So let's try this out. Rich Brown is going to read my Twitter feed and tell me what his computers would make of it.
BROWN: You've got one in here: Google and publishers reach deal on book scanning. So one of the things here, reaching a deal, is actually seen as a positive phrase, it's associated with Google; that could actually be very good news on this particular company.
MARRITZ: We go through a half dozen of these. Tweets with words like "love" get a positive score. "Disappointment" and "jerks" get negative scores. So computers can read the news and opinion like people do, but way, way faster. But does that really give anyone an edge?
JAMES LIEW: I'm not yet convinced that this is particularly the right approach.
MARRITZ: James Liew teaches finance at NYU's Stern Business School and has a small hedge fund. He studies sentiment analysis, but he's not using it to invest. Not yet, anyway.
LIEW: 'Cause a lot of the research that's coming out right now is funded by the sentiment providers. So they're looking and they're trying to sell this data, and so the research tends to be a little bit on the biased side.
MARRITZ: Liew says it's possible someone is getting rich off tweets and Facebook posts, but you probably won't hear about it. Because when people on Wall Street are making tons of money, they don't tend to proclaim it on Twitter.
For NPR News, I'm Ilya Marritz in New York.