Risk No. 1: Turnover
The risk of an undiversified stock of debt is known in finance as turnover risk. In the months ahead, as those T-bills mature, the Treasury faces the risk of refinancing those securities at much higher rates. Higher interest payments would only add to the cost of carrying the original debt.
Risk No. 2: Insufficient bank reserves
The unusual period from 2023 to 2024, characterized by high inflation, tight monetary policy and increased short-term debt issuance, created the basis for low levels of bank reserves and, consequently, eroded the safety of the banking industry.
When the returns on T-bills were within the range of longer-term Treasury notes, investors parked their holdings in the Fed’s overnight money market facilities.
Because funds in those facilities are essentially cash, the level of bank reserves surged, moving from ample to abundant.
This abundance was reflected in the significant size of the Fed’s overnight repo facility before 2025. But as money markets bought up T-bills in 2025, the overnight repo facility was drained, sending bank reserves from abundant to merely ample and possibly worse.
The minutes of the December meeting of the Federal Open Market Committee pointed to members’ concerns about this decline, particularly with the April tax season approaching.
In response, the Fed has been purchasing T-bills, injecting cash into the financial system and maintaining ample bank reserves.
Risk No. 3: Distortions in monetary policy
The reliance on T-bill issuance is affecting how monetary policy is transmitted to the financial sector. The repo market has become a major source of funding for the economy, and the resulting distortions—wider spreads between repo (market) rates and the administered federal funds rate—need to be managed.
To address what the Fed sees as a reluctance to park funds in its repo facility, the FOMC minutes suggested that the Fed clarify the purpose of this tool, convey that the funds are meant to be used when warranted, and eliminate the existing limits on their use.
Risk No. 4: Unsustainable debt
Finally, the government’s debt has been growing since 2016. The ratio of debt to gross domestic product approached 100% in 2020 during the pandemic and again in 2024 and 2025 when government spending matched the economy’s output.
While this ratio does not determine the economy’s ability to generate output, and while we have yet to see interest rates surge because of a loss of confidence in the country’s ability to manage its debt, more and more tax revenues are going toward the cost of servicing that debt.
That implies the possible crowding out of private investment and the degradation of growth, as is the case in Japan.