Facebook shares freed, fall

The social networking site's shares fell 5.1% to 26.81 after 156 mil shares held by insiders and employees were freed for trading, the fourth of five stock lockup expirations. Facebook (FB) shares fell 5% on average during lockup expiration days in Aug. and Oct. On its third and biggest lockup expiration day in Nov., the stock unexpectedly rose 12.5%. Lockup restrictions are designed in large part to avoid a flood of shares into the market in the months following an initial public offering .