In 2002, United Airlines, one of the largest air carriers in the United States, filed for bankruptcy protection, due to the downturn in the industry following the terrorist attacks of September 11, 2001. The company engaged in restructuring and emerged from bankruptcy protection later in 2002. Six years later, on September 9, 2008, a worker at a Miami investment advisory firm did a Google search on bankruptcies and got back search results that included a story about the 2002 bankruptcy filing by United Airlines. The employee mistook the news for a current (2008) story and included it in a subscription newsletter that was distributed nation-wide through Bloomberg. Within minutes, 15 million shares of United Airlines stock had been sold before trading on the stock was halted, and United Airlines' stock price had plummeted 75 percent (down from $12.30 to $3 a share) before someone realized it was an old news story and a correction was posted. Explain what happened using efficient market theory.