Bonds and rates · Analysis
Treasury bill yields: what remains after tax and inflation?
As short-term rates attract attention, compare Treasury bill proceeds with inflation and your own tax treatment rather than the headline yield alone.
Why short-term yields are in focus
September’s policy-rate increase makes short-term saving alternatives a timely comparison. Treasury bills pay face value at maturity and are sold at a discount or at par. A bill’s quoted annualized yield is not the percentage gain earned over a short holding period. This article uses hypothetical numbers rather than a live auction quotation.
Translate a quote into cash
If a bill costs $9,900 and pays $10,000 at maturity, its dollar interest is $100 and its holding-period return is about 1.01%. The number of days determines the annualized interpretation. The same $100 gain over different terms describes different annual rates. Do not compare that raw percentage directly with a deposit APY.
Then account for taxes and prices
Suppose a hypothetical investment returns 4% over a full year and all interest faces an illustrative 22% federal tax rate. The after-tax gain is 3.12%. With 3% inflation, the exact real result is 1.0312 / 1.03 − 1, about 0.12%. This excludes other income effects and costs. Actual tax circumstances differ.
Access is part of the comparison
A bill held to maturity and one sold earlier do not necessarily deliver the same proceeds. Platform transfer procedures, settlement, and fees matter when cash is needed quickly. Treasury interest generally has different state and local income-tax treatment from bank interest, so after-tax comparisons can vary by location.
A practical reading of the headline
Compare dates, net proceeds, and accessible cash rather than assuming a higher policy rate guarantees a particular bill yield. Read our Treasury bills versus CDs analysis before comparing offers. A nominally larger balance can still provide less buying power if inflation or costs exceed its gain.