AIG, Magna, Activision Blizzard are big movers

The following stocks were among those that moved substantially or traded heavily Friday on the New York Stock Exchange:

NYSE:

American International Group Inc., down $3.80 at $35.48

The insurance company had a profitable quarter as the value of its investments rose, but the CEO warned that future results will be choppy.

International Game Technology, up $1.62 at $20.18

Despite a loss in the fourth quarter, CEO Patti Smith said there was an "incremental" improvement in casino operators' demand for the company's slot machines.

Magna International Inc., up $5.80 at $50

Two days after the collapse of the auto supplier's deal to buy General Motors' European division Opel, the Canadian company posted an unexpected profit.

Ormat Technologies Inc., down $2.29 at $36.21

An analyst downgraded the geothermal plant operator, saying 2010 product revenue is uncertain amid delays of several projects.

K12 Inc., up $2.14 at $17.94

Expectations that enrollments will keep rising next year led the educational services provider to issue a higher-than-expected sales forecast.

NASDAQ:

Activision Blizzard Inc., up 38 cents at $11.25

The company's CEO said its "Call of Duty: Modern Warfare 2," which comes out next week, is on track to be the largest video game launch of all time.

American Science & Engineering Co., up $3.57 at $73.92

The X-ray detection system maker's profit jumped 45 percent as security agencies increased their orders.

Nvidia Corp., up 89 cents at $13.16

Strong demand from customers bolstered results at the graphics chip maker, and its sales forecast topped Wall Street expectations.