Date: Oct. 15, 2008
(BEN STANSALL/AFP/Getty Images)
Circumstances: That four of the worst 10 days in S&P history took place within two months of each other says something about the severity of the 2008 meltdown. The spiraling subprime crisis had already consumed Bear Stearns and knocked the S&P 20 percent off its all-time peak when the September 15 collapse of Lehman Brothers broadsided the market. The October 15 decline came after an 11-percent rally earlier in the week and was followed by a 4.2-percent rally the next day. Possibly the only thing on the rise was Dramamine sales.