TORONTO - BlackBerry maker Research In Motion (RIM) has reported a profit of $643 million for the first quarter of the year, compared to $518.3 million posted during the previous quarter.

However, its quarterly revenue was slightly dwon at $3.42 billion from $3.46 billion in the previous quarter. But it is still up 53 percent from $2.24 billion during the same period last year.

BlackBerry added about 3.8 million net new subscribers accounts during the quarter, taking its total subscriber base to nearly 28.5 million.

During the quarter, RIM sold over 7.8 million smart phones that accounted for 81 percent of its revenue. Services accounted for 13 percent of the revenue.

The wireless communications giant, which is based in Waterloo near here, forecast the second quarter revenue in the range of $3.45 billion and $3.70 billion.

RIM also expected to add up to more than 4.1 million new subscribers in the next quarter.

“We are starting fiscal 2010 with strong financial performance and impressive market share gains, including a 55 percent share of the US smart phone market according to IDC’s latest estimate,” RIM co-CEO Jim Balsillie said.

“The industry leading BlackBerry product portfolio is driving strong customer demand around the world and our penetration of new market segments continues to expand.

“We are particularly excited about the strength of our product portfolio for fiscal 2010 and we are looking forward to driving continued growth and profitability in our business throughout the remainder of the year,” he added.

But the better-than-expected results by the BlackBerry maker failed to enthuse investors as its stock slipped more than four percent Friday.

The RIM shares closed down $3.83 at $82.97 on the Toronto Stock Exchange (TSX).

Last week, the company’s stock traded at $95.

RIM shares had sunk to $44.60 during the first week of December. Since then, the company’s stock has almost doubled.