Treasuries rose Monday on speculation that credit-market turmoil may be widening. The gains pushed yields on U.S. 10-year notes to the lowest since May 13 as financial stocks fell amid speculation that American International Group Inc. will post a loss and Korea Development Bank may be reconsidering a possible bid for Lehman Brothers Holdings Inc.

“This is the longest-running horror movie that any of us has ever had to deal with,” said T.J. Marta, a strategist at RBC Capital Markets in New York.