That's because the stock market didn't crash in 2009-we were coming out of a recession. Stock Market was already down. --"The 2009-10 flu pandemic or Swine Flu began March 17, 2009 in Mexico. At that time, the U.S. was emerging from the 2008 financial crisis and stocks were significantly undervalued. Just over four months from its inception, clinical trials for the Swine Flu vaccine began. In October 2009, the virus peaked in the U.S. before officially ending August 11, 2010. From the start of the virus to its finish, the Dow had risen over 40%."