The Treasury Department says it will offer investors Treasury securities with variable interest rates, similar to those on some home mortgages.

Officials said actual sale of the new type of securities is at a least a year away because of the time needed to modify government computer systems to handle the floating-rate securities.

Treasury says it will continue to study a second unconventional way to sell government debt that would offer negative yields. Investors would, in effect, pay the government for the privilege of socking their money in ultra-safe Treasurys. No decision has been made yet on whether to proceed with negative yield securities.

Global investors have been shifting money into Treasurys out of fear of other types of securities, especially those linked to Europe's debt crisis.