Shares in BlackBerry maker Research In Motion fell below $10, the lowest point in nearly eight years, amid growing concerns about the outlook for the troubled smartphone maker.
RIM shares tumbled 5.85 percent to close at $9.66, the first close below $10 since late 2004.
Smartphone pioneer RIM risks falling further behind the competition in the market now being dominated by Apple's iPhone and Android platform makers like Samsung of South Korea.
The company warned last week it could report a loss in the current quarter and said it had hired investment firms to study strategic options.
A survey by research firm IDC showed smartphones powered by Google's Android software accounted for 59 percent of the global market in the first quarter of 2012, with 23 percent for Apple's iPhones.
That left just 6.4 percent for BlackBerry, compared with 13.6 percent a year ago.