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Treasury Bills vs CDs vs High-Yield Savings in 2026

A detailed 2026 comparison of Treasury bills, bank CDs, and high-yield savings accounts, including yield, safety, liquidity, taxes, FDIC coverage, and best use cases.

5 min read

Treasury bills, certificates of deposit, and high-yield savings accounts can all be reasonable places for low-risk cash. The best choice depends on when you need the money, how much state tax you pay, whether you need FDIC insurance, and whether you want a fixed maturity.

In 2026, savers should compare after-tax yield, not just the advertised rate. Treasury bill interest is generally exempt from state and local income tax. Bank interest and CD interest are usually taxable at both federal and state levels.

If you want a direct Treasury strategy, see T-Bill Ladder in TreasuryDirect 2026. If you are comparing fund-based options, read Money Market Fund vs High-Yield Savings.

Quick Comparison

Feature Treasury bills Bank CDs High-yield savings
Issuer U.S. Treasury Bank or credit union Bank or credit union
Typical term 4 to 52 weeks Months to years No fixed term
Principal guarantee Backed by U.S. government if held to maturity FDIC/NCUA insured within limits FDIC/NCUA insured within limits
Rate lock Yes, at auction/purchase Yes, usually No, rate can change
Liquidity Hold to maturity or sell if marketable Early withdrawal penalty or brokered CD sale High
State tax Generally exempt Usually taxable Usually taxable
Best for Known short-term dates Fixed-rate savings Emergency cash

Treasury Bills

Treasury bills are short-term U.S. government securities. They are sold at a discount and mature at face value. The difference is your interest.

Common maturities include:

  • 4 weeks
  • 8 weeks
  • 13 weeks
  • 17 weeks
  • 26 weeks
  • 52 weeks

T-bills are useful when you have a known date for the cash: taxes, tuition, a down payment, insurance premiums, or a planned purchase. They can be bought through TreasuryDirect or through many brokerages.

The main advantage over bank products is state-tax treatment. A T-bill yielding slightly less than a CD may still win after tax for savers in high-tax states.

CDs

Bank CDs offer a fixed rate for a fixed term. Traditional bank CDs are typically FDIC insured within limits when issued by an insured bank. Credit union share certificates may have NCUA coverage.

CDs can be attractive when:

  • the rate is clearly higher than T-bills after tax
  • the term matches your cash need
  • you want FDIC insurance
  • you do not want to manage Treasury auctions

The tradeoff is liquidity. A bank CD may charge an early withdrawal penalty. A brokered CD may need to be sold at market value, which can be above or below the amount you paid.

For callable CD risks, see Brokered CDs: Safe, Callable, and Noncallable Explained.

High-Yield Savings

A high-yield savings account is usually best for money that needs to remain flexible. The rate can change at any time, but access is easier than with a T-bill or CD.

Best uses:

  • emergency fund
  • near-term bills
  • payroll buffer
  • money you may need on short notice
  • cash waiting for a known decision

The downside is reinvestment risk. If interest rates fall, the bank can reduce the savings rate quickly.

How to Compare After-Tax Yield

Use after-tax yield:

after-tax yield = stated yield x (1 - tax rate that applies)

For Treasury bills, state income tax usually does not apply. For CDs and savings, both federal and state income tax may apply.

Example: A saver in a 24% federal bracket and 5% state bracket compares:

  • T-bill: 4.50%
  • CD: 4.70%

Approximate after-tax yields:

  • T-bill: 4.50% x (1 - 0.24) = 3.42%
  • CD: 4.70% x (1 - 0.29) = 3.34%

Even though the CD has a higher stated rate, the T-bill can be better after tax.

Safety: Treasury Backing vs FDIC Insurance

Treasury bills are backed by the U.S. government. Bank deposits are insured by the FDIC up to applicable limits, generally $250,000 per depositor, per insured bank, per ownership category.

Do not confuse a brokerage account with FDIC insurance. A Treasury bill held in a brokerage account is a security, not a bank deposit. A brokered CD may have FDIC insurance if properly titled and within limits, but the brokerage account itself is covered by SIPC custody protections, not FDIC deposit insurance.

Which Should You Use?

Use high-yield savings for immediate liquidity.

Use T-bills for known short-term dates when you want state-tax efficiency and can hold to maturity.

Use CDs when the after-tax rate is better than Treasuries, the term fits, and FDIC or NCUA coverage is clear.

Many households use all three: savings for emergency cash, T-bills for scheduled expenses, and CDs when banks offer unusually strong rates.

Bottom Line

Treasury bills, CDs, and high-yield savings are not interchangeable. For flexible emergency cash, high-yield savings is usually easiest. For known dates and state-tax efficiency, T-bills are strong. For fixed bank yields with deposit insurance, CDs can win if the rate compensates for the liquidity tradeoff.

Sources

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