On Monday, Compuware (CPWR.DL) shareholder Elliott Management, which owns an 8% interest in the company, offered to buy the rest of the company for $11 a share, cash, or $2.3 billion in all.

In a letter submitted to the company's board of directors, Elliott argued that its offer amounted to a sizable premium to what Compuware's shares have fetched in the market recently and called its offer "a compelling opportunity that your stockholders will find extremely attractive."

Other shareholders appear to agree. Compuware shares rose sharply in response to Elliott's offer, and at least one other shareholder, Sandell Asset Management, which owns 2.5% of Compuware's shares, has sent the board of directors a letter urging acceptance of the offer.

Further complicating matters, Compuware itself is in the process of trying to get its Covisint subsidiary listed in a new IPO.

Shares of Compuware closed the day up 12.9% at $10.76 per share.