The US Treasury Department estimates that it will need to borrow around $1 trillion a year for the next three fiscal years.
US savers, China, and OPEC have all traditionally been big buyers of Treasurys, but they may be close to tapped out.
If interest rates rise as expected, it could be even harder for the government to borrow what it needs.
Amid the Fed's balance sheet unwind, the Treasury needs are rising.
The Treasury Department estimated that it will borrow $955...