Compuware, the business software maker, is being included in today’s Insider Purchases & Share Buybacks because of the CEO, Peter Karmanos’ recent insider purchase and the potential IPO spinoff of its Covisint division. Late last night, Crain’s Detroit Business reported that Compuware is exploring selling its Covisint division in a 1 billion IPO, while still maintaining a 50% ownership stake in the company. It hopes to bring the company to the public market place next year and has already hired Morgan Stanley to explore the opportunity further.

On Friday, it was reported that MGIC Chief Executive, Curt Culver, purchased 50,000 shares for an average price of $19.77, bringing his total holdings to 402,999 shares. Along with his purchase, the president and multiple directors of the company also bought shares. I wrote about these insider trades on Columnist Conversations right when the news was released. I said remain cautious and referenced insider buying at Thornburg Mortgage (TMA) did not resuscitate that stock.

EasyStockAlerts.com reports that Eastman Chemical Company said its Board has approved the repurchase of up to $700 million of Eastman common stock, bringing the total of share repurchases authorized in 2007 to $1 billion. The company said that the $300 million in share repurchases authorized by the Board in February 2007 were completed during the third quarter.

Republic Airways announced it will repurchase 1,555,000 shares of its common stock from WexAir RJET LLC, the company's former majority stockholder. The shares will be repurchased at a price of $20.90 per share, totaling $32,499,500. This purchase is authorized under a previously announced $100 million share repurchase program. Republic Airways Holdings Inc. operates Chautauqua Airlines, Inc., (Chautauqua Airlines), Republic Airline Inc. (Republic Airline) and Shuttle America Corporation (Shuttle America).

NewMarket said its Board approved a share repurchase program that authorizes management to repurchase up to $50 million of NewMarket’s outstanding common stock until December 31, 2009.

Tim Hortons announced its Board has authorized a $200 million share repurchase program. As of October 25, 2007, Tim Hortons had 187,085,281 shares outstanding. Tim Hortons Inc. is quick-service restaurant chain in Canada.