Sbarro Inc., the 800-restaurant U.S. pizza chain in bankruptcy, has seen signs of interest from 31 potential bidders ahead of an auction for which it seeks initial offers by April 14, Bloomberg News reported yesterday. Of 114 possible buyers contacted, 31 signed confidentiality agreements to learn more about Sbarro, Adam Keil, a managing director at investment bank Moelis & Co., said in an April 4 in court filing. Sbarro’s secured lenders already have a proposal to buy the company under a reorganization plan that provides for an auction to test the market for higher bids. The plan has support of holders of 98 percent of secured lender claims, Keil said. The winning bidder must pay the company’s bankruptcy loans in full and offer more than $500,000 more than the $35 million credit bid made by the secured lenders.