Research in Motion's profit is up significantly

Research in Motion Ltd.'s fourth-quarter profit soared as it released new devices and won market share. The shares fell after sales trailed analysts' estimates and the company disclosed a formal probe by regulators.

Net income rose to $187.9 million, or 99 cents a share, from $18.4 million, or 10 cents, a year earlier, the company said. Sales climbed 66% to $930.4 million, missing the $935.4 million average estimate of analysts in a Bloomberg survey.

The company also said that an informal inquiry into the company's stock option practices by the U.S. Securities and Exchange Commission is now a formal probe.

Shares of Research in Motion, based in Waterloo, Ontario, fell $9.92, or 6.8%, to $136.10 in extended trading.