Facebook Inc. slumped to a record low after a pair of brokers cut their price targets on the stock, citing the combined weight of massive share lockups and signs of a weakening advertising business at the social network. Bank of America Merrill Lynch and BMO Capital Markets both cut their price targets on Facebook. A major issue weighing on Facebook is the expiration of post-IPO share lockups. About 271 million shares were released in mid-August, while more than 1.3 billion shares will become available for trading by mid-November. Investors worry the influx will push down the price if insiders like early investors and employees rush to sell their shares.