Within hours of Tekelec announcing its intended acquisition by a group of private equity firms for about $780 million, some investors were calling foul, saying the deal undervalues the company by hundreds of millions. (See Tekelec to Be Acquired.)

Tekelec, which today also reported its third-quarter results, is set to be acquired by a consortium of firms led by Siris Capital Group for $11 per share in cash, an 11 percent premium over the closing price last Friday, and a 38 percent premium over the 30-day trading average closing price.

But financial law firm Tripp Levy PLLC has announced an "investigation" into the deal, stating that analysts value the firm at $16 per share, nearly 46 percent higher than the price agreed with the Siris consortium.

At $16 per share, Tekelec would be valued at more than $1.1 billion. Tekelec shares were up $1.12 (11.31 percent) to $11.02 each in early trading Monday.

Tekelec today announced third-quarter revenues of $106.2 million and earnings before one-time costs (also known as non-GAAP earnings) of $0.01. (See Tekelec Reports Small Q3 Profit.)

The vendor has diversified in recent years from its traditional telecom signaling sector into policy management and subscriber data management with a couple of Service Provider Information Technology (SPIT)-related acquisitions. And now it's one of the leaders in the emerging Diameter routing sector. (See Tekelec on a Tear and Tekelec Splashes $165M on SPIT Specialists.)

— Ray Le Maistre, International Managing Editor, Light Reading