The gulf between bulls and bears has never widened so quickly inthe $12 trillion market for U.S. government bonds.

The proportion of investors betting on gains or losses inTreasuries, rather than holding a neutral view, almost doubled thisyear to 51 percent, a client survey by JPMorgan Chase & Co.showed. The 23 percentage-point jump is the most for the periodsince the top-ranked firm for U.S. fixed-income research byInstitutional Investor magazine began its weekly survey in2003.

With Treasury yields at historically low levels, the stakes arerising as the Federal Reserve cuts back the bond buying that's helddown borrowing costs on trillions of dollars of debt fromgovernments to companies and individuals. The debate pits PacificInvestment Management Co.'s Bill Gross, who says yields can staylow because growth and interest rates won't return to pre-crisislevels, against market-rules theorist Robert Farrell, who contendsasset prices always revert toward the average.