Stock Market Reaction to the Challenger Disaster

In part II of Chapter One, Surowiecki discusses the stock market reaction to the Space Shuttle Challenger Disaster.  Here is the live CNN broadcast of the shuttle launch.

Here is the extract from the The Wisdom of Crowds that deals with the stock market reaction to the Challenger disaster.

At 11:38 am on January 28, 1986, the space shuttle Challenger lifted off from its launch pad at Cape Canaveral. Seventy-four seconds later, it was ten miles high and rising. Then it blew up. The launch was televised, so news of the accident spread quickly. Eight minutes after the explosion, the first story hit the Dow Jones News Wire. The stock market did not pause to mourn. Within minutes, investors started dumping the stocks of the four major contractors who had participated in the Challenger launch: Rockwell International, which built the shuttle and its main engines; Lockheed, which managed ground support; Martin Marietta, which manufactured the ship's external fuel tank; and Morton Thiokol, which built the solid-fuel booster rocket.

Twenty-one minutes after the explosion, Lockheed's stock was down 5 percent, Martin Marietta's was down 3 percent, and Rockwell was down 6 percent. Morton Thiokol's stock was hit hardest of all. As the finance professors Michael T. Maloney and J. Harold Mulherin report in their fascinating study of the market's reaction to the Challenger disaster, so many investors were trying to sell Thiokol stock and so few people were interested in buying it that a trading halt was called almost immediately. When the stock started trading again, almost an hour after the explosion, it was down 6 percent. By the end of the day, its decline had almost doubled, so that at market close, Thiokol's stock was down nearly 12 percent. By contrast, the stocks of the three other firms started to creep back up, and by the end of the day their value had fallen only around 3 percent.

What this means is that the stock market had, almost immediately, labeled Morton Thiokol as the company that was responsible for the Challenger disaster. The stock market is, at least in theory, a machine for calculating the present value of all the "free cash flow" a company will earn in the future. (Free cash flow is the money that's left over after a company has paid all its bills and its taxes, has accounted for depreciation, and has invested in the business. It's the money you'd get to take home and put in the bank if you were the sole owner of the company.) The steep decline in Thiokol's stock price--especially compared with the slight declines in the stock prices of its competitors--was an unmistakable sign that investors believed that Thiokol was responsible, and that the consequences for its bottom line would be severe.

As Maloney and Mulherin point out, though, on the day of the disaster there were no public comments singling out Thiokol as the guilty party. While the New York Times article on the disaster that appeared the next morning did mention two rumors that had been making the rounds, neither of the rumors implicated Thiokol, and the Times declared, "There are no clues to the cause of the accident."

Regardless, the market was right. Six months after the explosion, the Presidential Commission on the Challenger revealed that the O-ring seals on the booster rockets made by Thiokol--seals that were supposed to prevent hot exhaust gases from escaping--became less resilient in cold weather, creating gaps that allowed the gases to leak out. (The physicist Richard Feynman famously demonstrated this at a congressional hearing by dropping an O-ring in a glass of ice water. When he pulled it out, the drop in temperature had made it brittle.)

In the case of the Challenger, the hot gases had escaped and burned into the main fuel tank, causing the cataclysmic explosion. Thiokol was held liable for the accident. The other companies were exonerated. In other words, within a half hour of the shuttle blowing up, the stock market knew what company was responsible. To be sure, this was a single event, and it's possible that the market's singling out of Thiokol was just luck. Or perhaps the company's business seemed especially susceptible to a downturn in the space program. Possibly the trading halt had sent a signal to investors to be wary. These all are important cautions, but there is still something eerie about what the market did. That's especially true because in this case the stock market was working as a pure weighing machine, undistorted by the factors--media speculation, momentum trading, and Wall Street hype--that make it a peculiarly erratic mechanism for aggregating the collective wisdom of investors. That day, it was just buyers and sellers trying to figure out what happened and getting it right.

Here is a short video of physics professor Richard Feynman giving his evidence to the Rogers Commission.



The Maloney and Mulherin paper is available for download here, with further discussion here.They cannot find an explanation as to how the information about the fault with Morton Thiokol's O-rings came to be reflected in the stock price so quickly. Their conclusion is that this may be a "perplexing situation that while markets appear to work in practice, we are not sure how they work in theory." If they watched a bit of Who Wants To Be A Millionnaire they would be better able to explain this using a simple model of Information Aggregation.