by: Brian Womack | Bloomberg BusinessWeek

Facebook Inc.’s 6.3 percent drop yesterday, after the end of restrictions on share sales by its biggest investors, was the second-largest post-lock-up decline among companies that have gone public since January 2011.

Only social-game maker Zynga Inc. tumbled more, losing 7.9 percent, on the first day that insiders could start selling their stakes, data compiled by Bloomberg show.