The Treasury is working on allowing investors to bid on securities that offer negative interest rates, another sign that officials expect borrowing costs to stay very low for a long time.
The government also is planning to issue floating-rate notes for the first time, but said such securities would not be brought to market for at least another year.
While no decisions has yet been made on negative-rate bids, the Treasury is encouraging market participants to report any operational concerns they might have with Treasury bill auctions that settle at negative rates.
Negative rates effectively mean investors are paying the government to lend it money, presumably due to concerns about potential losses in riskier assets.
Late last year, some Treasury bills trading in the secondary market were paying a negative yield because strong investor demand had pushed up prices so much, and some four-week bill auctions settled at a rate of zero percent. The Treasury noted there have been no negative rates this year.
Germany and France have experienced negative yields recently as panic about southern European states drove investors into the relative safety of the continent's two largest economies.
The Treasury's move could bolster concerns that the United States and Europe may be heading for a Japan-style period of sputtering economic growth and very low if not negative inflation rates.
The Federal Reserve has already indicated it expects to leave official rates near zero until at least late 2014, and some analysts think it could push that date further into the future at a two-day meeting that ends this afternoon.
In its August refunding announcement on Wednesday, the Treasury said it will borrow $72 billion over the coming quarter, adding that it is planning to eventually issue floating-rate notes and working on allowing investors to bid on negative-rate securities.
The government will issue $32 billion in three-year notes, $24 billion in 10-year notes and $16 billion in 30-year bonds.
The United States is on track to reach the statutory debt limit near the end of 2012 but has enough wiggle room to stay afloat until early 2013, the Treasury said.
Floating rate notes would attract investors who want to be sure they don't miss out on higher returns if interest rates begin to move higher.