Any selloff in Treasuries and the dollar following Standard & Poor's first ever downgrade of the U.S. from AAA is likely to be short-lived amid slowing economic growth and Europe's debt crisis, according to Wall Street banks.

JPMorgan Chase & Co. said a drop in Treasuries from the ratings cut is unlikely to be “sustained,” while Citigroup Inc. said dollar selling isn't forecast to be entrenched. Barclays Plc said the downgrade shouldn't be “significant,” and UBS AG said the top ranking for U.S. short-term debt will prevent money funds from being forced to react.

For all the handwringing over the credit-rating cut, bond investors from Wall Street banks that trade directly with the Federal Reserve to policy makers in China and Russia are likely to retain their holding of Treasuries as they see few alternatives to the world's deepest and most liquid market. The dollar remains the world's reserve currency even as S&P cut the U.S. one level to AA+ while keeping the outlook at “negative” on Aug. 5, citing the political failure to reduce record deficits while Moody's Investors Service and Fitch Ratings affirmed their AAA credit ratings for the U.S. on Aug. 2.