Groupon stock plunges to record low By: MarketWatch August 14, 2012 at 10:45 AM EDT Shares of Groupon fall to record low on disappointing results. NCR sinks on an analyst downgrade, while blue chips Cisco and Hewlett-Packard slip as well. Read More >> Related Stocks: Apple Cisco Systems Groupon Cl A Hewlett-Packard Juniper Networks Microsoft NCR Corp Texas Instruments