At least one of the biggest shareholders of Great Wolf Resorts stock is questioning the deal announced Tuesday for Apollo Global Management, a New York private equity firm, to buy the Madison indoor water park company for $5 a share. With the share price above Apollo’s $5 offer, it could be an indication of “investors guessing it’ll be sold at a higher price,” said Jim Seward, associate professor at the UW-Madison School of Business and faculty director of the Nicholas Center for Corporate Finance and Investment Banking.