4 Min Read NEW YORK (Reuters) - The cost of borrowing U.S. 10-year Treasuries in the overnight repurchase, or repo market, went deeply negative on Thursday, analysts said, as investors sought to short the notes, causing market stress. FILE PHOTO: U.S. one hundred dollar notes are seen in this picture illustration taken in Seoul February 7, 2011. REUTERS/Lee Jae-Won Negative rates in the repo market, which is important to the financial system, with trillions of dollars in short-term loans traded daily, partly reflect uncertainty about how long the U.S. Federal Reserve will keep its easy monetary policy. “There is more market stress right now because the market is very volatile,” said Scott Skyrm, executive vice president at broker-dealer Curvature Securities.