• by Wayne Friedman , May 7, 2009

Cable operator Cablevision Systems' stock rocketed up 17% in mid-day trading to $21.37.

The stock moves come on company news that its first-quarter results swung to a net profit of $20.2 million versus a loss of $31.6 million for the first quarter of 2008.

Cablevision also said it had received authorization from its directors to spin off its Madison Square Garden group -- which includes the New York Knicks, the New York Rangers, the MSG regional sports network, the Madison Square Garden building, and other assets.

Quarterly revenue climbed 11% to $1.9 billion from $1.72 billion in the period before -- on par with analysts' expectations. Its cable television revenue rose 5% over the first quarter of 2008, to $1.27 billion.

Digital video customers were up a bit, by 9,400 -- or 0.3% -- from the fourth quarter of 2008. Digital subscribers rose nearly 7% compared with last year's first quarter. As with most cable operators, basic video subscribers declined. For Cablevision, this meant a loss of 6,300 -- or 0.2% -- from the December quarter, and of 23,100 from the first quarter of 2008.

For some of its newer products, broadband subscribers rose by 141,700, or 6%, from the year-ago quarter. Overall revenue per cable customer climbed over 5% to $136.55. For its phone subscribers, customers were up 51,400 or 2.7% from December 2008, and 244,500 or 14.5% from March 2008.

Good results continued at the company's cable networks -- AMC, Independent Film Channel, WE: Women's Entertainment and various regional sports networks -- where revenue climbed 11% to $249.3 million. Operating income at Rainbow Media, its cable network group, climbed 40.2% higher to $38.8 million.

At its Madison Square Garden Group, revenue grew 16% to $271.3 million on a narrower net loss of $2.2 million versus a net loss $19.7 million.