Treasury Bills vs. High-Yield CD Calculator (2026): Why NY & NJ Savers Keep More After Tax
Compare after-tax yields on US Treasury Bills (4-week to 52-week T-Bills) against bank CDs and High-Yield Savings Accounts. See why federal state/local tax exemption gives T-Bills a massive edge in NYC, NY, NJ, and MA.
By Pablo Cirre Gómez and East Corp Capital Quantitative Desk
NEW YORK — Sit down at a kitchen table anywhere from Manhattan and Westchester to Bergen County, Fairfield County, or Back Bay Boston, and one financial question quickly dominates the conversation around treasury bills vs. high-yield cd calculator (2026): How do the 2026 statutory rules, interest rates, and regional tax brackets actually translate into real dollars for your household or business? Under 31 U.S.C. § 3124(a), interest earned on US Treasury Bills, Notes, Bonds, and Treasury Money Market Funds is 100% exempt from state and municipal income taxes.
US Treasury Bills vs. Bank CDs After-Tax Yield Calculator
Compares state-and-local-tax-exempt US Treasury bills against fully taxed bank CDs in NYC, NY, NJ, MA, and PA, and computes the exact Tax-Equivalent CD APY.
How Does The Statutory Exemption Formula: Why CDs Lose in High-Tax States Impact Your Bottom Line?
When comparing cash management rates on emergency funds, home down-payment escrows, or corporate treasury balances, retail savers frequently compare the headline Annual Percentage Yield (APY) of an FDIC-insured Bank CD against the yield-to-maturity of a 3-month or 6-month US Treasury Bill. In high-tax Northeast states, that comparison is mathematically flawed.
Under federal statute 31 U.S.C. § 3124, obligations of the United States Government are exempt from taxation by any state, county, or municipality. The formula to calculate the Tax-Equivalent CD Yield required to match a Treasury Bill yield ($Y_T$) given your federal marginal rate ($t_F$) and combined state/city marginal rate ($t_S$) is:
Equivalent CD Yield = Y_T × (1 - t_F) / (1 - t_F - t_S)
| Resident Jurisdiction | State + Local Marginal Tax | Gross Annual Interest | Net After-Tax (Bank CD) | Net After-Tax (T-Bill) | Annual T-Bill Tax Advantage | Equivalent CD APY |
|---|---|---|---|---|---|---|
| Florida (Miami / Palm Beach) | 0.00% | $4,650 | $3,162 | $3,162 | $0 | 4.65% |
| Pennsylvania (Philadelphia suburbs) | 3.07% | $4,650 | $3,019 | $3,162 | +$143 | 4.87% |
| Connecticut (Stamford / Greenwich) | 6.99% | $4,650 | $2,837 | $3,162 | +$325 | 5.18% |
| New York State (Westchester / LI) | 6.85% | $4,650 | $2,843 | $3,162 | +$319 | 5.17% |
| New Jersey (Top Tier >$1M) | 10.75% | $4,650 | $2,662 | $3,162 | +$500 | 5.50% |
| New York City (NYS 6.85% + NYC 3.88%) | 10.73% | $4,650 | $2,663 | $3,162 | +$499 | 5.49% |
| New York City Top Bracket (NYS 10.9% + NYC) | 14.78% | $4,650 | $2,475 | $3,162 | +$687 | 5.94% |
Let’s Run the Numbers in Dollars: Comparing Florida (Miami / Palm Beach) vs. Connecticut (Stamford / Greenwich) in the Tri-State Corridor
Let’s run the numbers in dollars using verified 2026 benchmarks from our quantitative table above so you can see the exact gap before making a decision:
- Baseline Profile (Resident Jurisdiction: Florida (Miami / Palm Beach)): Produces a verified outcome of 4.65% (Equivalent CD APY), reflecting 0.00% and $4,650.
- Scaled Tri-State Profile (Resident Jurisdiction: Connecticut (Stamford / Greenwich)): Shifts the net figure to 5.18% (Equivalent CD APY). Interest from Bank Certificates of Deposit (CDs) and High-Yield Savings Accounts (HYSAs) is taxed as ordinary income at both the Federal level AND the State/NYC level (up to 14.776% extra in NYC).
How to Claim the US Government Interest Subtraction on Your NY & NJ Returns?
If you buy T-Bills directly at auction via TreasuryDirect or a brokerage account (Fidelity, Schwab, Vanguard), your broker reports the interest in Box 3 of Form 1099-INT (‘Interest on U.S. Savings Bonds and Treasury obligations’). On your New York State return (Form IT-201), this amount is automatically subtracted on Line 28 (U.S. government bond interest subtraction), removing it from both NY State and NYC taxable income.
If you hold a Treasury-only money market fund (such as VUSXX or FDLXX), check your fund provider’s annual U.S. Government Securities Income Percentage statement: New York requires at least 50% of the fund’s assets to be invested in qualifying direct US obligations at each quarterly close to claim the proportionate state tax subtraction.
To model how this interacts with the rest of your East Coast balance sheet, run your numbers in our NYC & NY State Paycheck Tax Calculator, compare housing and closing tax rules in our NYC Mansion Tax & Closing Cost Calculator, and benchmark after-tax fixed-income yields in our US Treasury Bills vs. Bank CDs Calculator.
Frequently Asked Questions
Do Repurchase Agreements (Repos) inside a money market fund qualify for NY State tax exemption?
No. New York State and California strictly exclude interest earned from repurchase agreements (repos)—even when collateralized by US Treasuries—from the state income tax exemption. To maximize NY/NYC tax savings in a money market fund, choose a 'Treasury Only' fund (typically 95%–100% direct T-Bills) rather than a 'Government' money market fund heavy in repos.
Are US Treasury Bills safer than an FDIC-insured CD above $250,000?
Yes. Bank CDs are insured by the FDIC up to $250,000 per depositor, per insured bank, per ownership category. US Treasury Bills are backed by the full faith and credit of the United States Treasury with no dollar cap, making them the institutional standard for $500k to $50M+ liquidity balances.