Treasury yields were also sinking in the bond market after a report showed U.S. manufacturing shrank again in August, as it continues to wilt under the weight of high interest rates. Manufacturing has been contracting for most of the past two years, and its performance for August was worse than economists expected.

If the Federal Reserve decides to cut its key interest rate by 50 basis points, it will be important to note how central bank officials characterize the need for a jumbo rate cut instead of a 25-basis-point cut,