Hot Stocks: Cablevision, Nortel Among Big Movers Wednesday

The majority of the most actively traded stocks on Wednesday were making big moves to the upside as investors reacted to merger news and earnings updates.

Cablevision Systems jumped 8% after the cable broadcasting company confirmed that the Dolan family will take it private for $10.6 billion. The offer of $36.26 a share is 20% above the controlling family's previous offer. The stock has almost doubled in the past year.

Nortel Networks issued first-quarter guidance above analysts' estimates, prompting gains of more than 5%. The Canadian networking company said it expects quarterly revenue to rise 4% to $2.48 billion, above analysts' forecast of $2.37 billion, and also maintained 2007 revenue guidance.

"Nortel is a well-positioned vendor and should continue to benefit from its CDMA and enterprise businesses in the near future," said Prudential analyst Inder Singh, in a client note Wednesday.

MasterCard shares advanced 10% amid heavy trading volume after the credit card company said first-quarter earnings and revenue rose due to growth in international cardholder purchases.

Time Warner rose more than 2% on above-average volume after it reported first-quarter profit that beat Wall Street expectations, boosted by subscriber growth and higher Internet advertising sales. The world's largest media company reported earnings of $1.2 billion, or 31 cents a share.

Cavium Networks surged 25% above its initial public offering price of $13.50 in its first day of trading. The specialty chipmaker, which priced the offering above its initial range of $10 to $12, began trading on the Nasdaq under the ticker symbol CAVM.