💵 31 U.S.C. § 3124 State Tax Shield

State-Tax T-Bill vs. HYSA Yield Matrix

High-income earners in high-tax jurisdictions face severe tax drag on commercial bank interest. Select your jurisdiction below to see your exact Tax-Equivalent Yield and net dollar advantage.

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13.30% Tax CA

California

Calculate your after-tax yield delta between U.S. Treasury bills and High-Yield Savings Accounts (HYSA) in California under 31 U.S.C. 3124. Compare state tax savings on 13.3% top brackets in real time.

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14.78% Tax NY

New York City

Compare net after-tax cash returns on U.S. Treasury bills vs HYSA for New York City residents. Calculate combined NY State (10.9%) and NYC municipal (3.876%) tax savings in real time.

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10.90% Tax NY

New York State (Outside NYC)

Calculate after-tax net interest yields between U.S. Treasury bills and high-yield savings accounts in New York State. See how 31 U.S.C. 3124 shields cash from 10.9% state tax brackets.

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9.00% Tax MA

Massachusetts

Compare Treasury bills vs HYSA for Massachusetts high earners. Calculate how 31 U.S.C. 3124 saves the 5% flat state tax plus 4% Fair Share Amendment surtax (9.0% total).

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10.75% Tax NJ

New Jersey

Calculate after-tax net yields between Treasury bills and bank savings accounts in New Jersey. Shelter cash interest from New Jersey 10.75% top marginal income tax.

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Workplace Match Priority

Company 401(k) Match Directory

Capture your full guaranteed 50% to 200% employer match before parking excess liquidity in short-term T-Bills.

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Equity Compensation

Tech Equity & RSU Vesting Hub

Model after-tax equity vesting waterfalls, cliff risks, and refresher stacking across 28 major tech employers.

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❓ Common Questions

Frequently Asked Questions on T-Bills vs. Bank Savings

Detailed tax and liquidity answers for high earners.

Why are U.S. Treasury bills exempt from state and local income taxes?

Under 31 U.S.C. Section 3124, obligations of the United States Government are exempt from state, municipal, and local taxation. While high-yield savings account (HYSA) interest is taxed as ordinary income at the state and municipal level, Treasury bill interest is completely shielded from state tax.

What is Tax-Equivalent Yield (TEY)?

Tax-Equivalent Yield is the pretax yield a fully taxable bank account must pay to match the after-tax yield of a tax-exempt security like a Treasury bill. The formula is: TEY = T-Bill Yield / (1 - State Tax Rate).

How much money do high earners in California and New York City save with T-Bills?

In California (13.3% state tax) and New York City (14.78% combined state and municipal tax), high earners save hundreds to thousands of dollars per year on liquid cash balances. For instance, on a $250,000 cash balance earning 4.65%, an NYC resident saves approximately $1,718 per year in state and city taxes alone.

📥 Cash Management Guide (PDF) One-Page Reference • Instant PDF

Download the State-Tax T-Bill vs. HYSA Strategy Blueprint (PDF)

Get our 1-page printable cheat sheet with state-by-state Tax-Equivalent Yield lookups, 31 U.S.C. Section 3124 exemption guidelines, and brokerage auto-roll setup guides.

  • ✓ State tax exemption formulas: California (13.3%), NYC (14.78%), NJ (10.75%)
  • ✓ Fidelity, Schwab, and Vanguard auto-roll execution workflows
  • ✓ Yield curve duration-matching and liquidity management steps

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