“It hasn’t been a good few weeks for investors with bearish bets on Research In Motion Ltd., the maker of BlackBerry wireless e-mail devices,” writes Cassell Bryan-Low in today’s Wall Street Journal.

“Shares of the Waterloo, Ontario, company — whose addictive gadgets some users nickname ‘CrackBerry’ — soared 51% late last month to $69.61 after the company posted stronger-than-expected third-quarter results and raised its fourth-quarter outlook.”

“And this month, taking advantage of its highflying stock price, the company announced plans to raise more than $900 million by issuing stock. While putting more shares into circulation can depress share prices, the company’s stock has continued to climb.”

“Indeed, the stock has roughly doubled in the past month, reaching $87.78 in 4 p.m. trading Tuesday on the Nasdaq Stock Market, up $4.13, after setting a 52-week high of $87.93 during the day. That is up sharply from a 52-week low of under $12.”

“Bearish bets against the stock, meanwhile, have continued to increase in recent months. Short sellers, expecting a stock to plunge, sell borrowed stock in the hope that they will profit by being able to buy the shares back later at a lower price for return to the lender. The number of RIM short positions not yet closed jumped 27% to 10.8 million shares as of Dec. 15, up from 8.5 million shares in mid-November.”

“By another measure, negative sentiment on RIM eased slightly in the latest month. The short-interest ratio, or the number of days it would take to cover all short positions, was 4.2 days in December down from 4.5 days in November. Still, that is up sharply from the ratio of 2.7 days in September.”

” ‘The stock is very volatile because the company has grown so fast,’ said Barry Richards, an analyst at Paradigm Capital Inc. in Toronto. ‘That volatility creates opportunities for people long and short.’ “

“RIM declined to comment, citing a quiet period related to its stock offering, which is expected to close Wednesday.”

“Over the long term, bears are focused on the company’s legal fight over its U.S. patent rights. In August, a court in Virginia stayed a ruling over patent infringements that could require the company to stop selling the BlackBerry devices in the U.S. The U.S. District Court for the Eastern District of Virginia also stayed its order, pending appeal, that RIM pay $53.7 million in damages and costs to closely held NTP Inc., of Arlington, Va., which was formed to defend the patents of a Chicago-area electrical engineer and inventor. The ruling stems from a 2001 statement of claim alleging BlackBerry infringes on eight patents controlled by NTP.”