The article discusses corporate bonds that are being offered by the supermarket chain Tesco. This week Tesco approached the bond markets with an unusual lure to creditors. Its long-term bonds included a covenant that would protect bondholders' interests in the unlikely event that Tesco is gobbled up. Bankers say it is not the first time that Tesco's bonds have included such a "change of control" clause. Other companies are being pressed to follow its lead. There are two reasons why. First is the pace and scale of takeover activity around the world, with bidders employing cheap debt in colossal volumes. Second, creditors that have lent with few strings attached in recent, easy-money years are learning to be a bit more demanding. The very attributes that attract bondholders to a borrower, such as large, stable cashflow to service debt, are the same that entice a leveraged buy-out (LBO) fund. So without change-of-control safeguards, the danger of being blindsided is growing. According to Louise Purtle, a strategist at CreditSights, a research boutique, two of the biggest recent deals in America, last year's $11.4 billion LBO of SunGard Data Systems, and Koch Industries' takeover of Georgia-Pacific, both gave bondholders an unwelcome surprise. In Europe KPN, a Dutch telecommunications group, sold bonds last week which included a change-of-control clause--a "sine qua non", says one Latin-speaking banker, because of the risk of a buy-out. And last month BAA, operator of London's biggest airports, faced a possible takeover bid just as it was issuing bonds with no change-of-control clause.