** Shares of major Wall Street banks sink in premarket trade, as a rush to safety pushes up bond prices and brings down yields

** Bank of America Group Corp falls the most among peers, down 2.5%, while heavyweights including Goldman Sachs Group, JPMorgan & Chase Co and Morgan Stanley shed more than 2%

** 10-year yields sink to a three-week low; the yield curve flattens after concerns over the Omicron coronavirus variant pushes up bond prices.

** Broad flattening of the yield curve indicates buying across most dated debt, although short-term yields see biggest drop

** U.S. money markets also push back expectations of 25 basis-point interest rate hike by the Federal Reserve to September 2022, versus July

** S&P 500 banks index, up 35.6% YTD, has benefited from expectations of Fed tightening in response to inflation

(Reporting by Ambar Warrick) ((Ambar.Warrick@thomsonreuters.com; +91-80-6182-2837;))