NEW YORK - Groupon's stock is tumbling as insiders are selling their shares after a post-IPO prohibition was lifted.

Employees and other insiders are required to wait before selling their stock following a company's initial public offering. Groupon's lock-up period expired on Friday. The company went public on Nov. 4.

Shares of Chicago-based Groupon Inc. fell 93 cents, or 8.7 per cent, to $9.71 in midday trading Friday. Earlier, the stock was as low as $9.53. That's the lowest since its IPO, which priced at $20.

Friday was a bad day for the overall stock market, too. A closely watched report showed that the U.S. economy added far fewer jobs than expected last month.