Right now, Treasury Bills and CDs appear to send a mixed message about which investment pays more. A top-tier CD from banks like Newtek or Bread Savings offers 4.20% or 4.15% APY respectively, while 4-week Treasury Bills yield 3.65% and 26-week T-Bills yield 3.68%. On the surface, CDs win by a comfortable margin. But the real answer depends on where you live—and it’s more nuanced than headline rates suggest.
If you live in a high-tax state like California, New York, or New Jersey, Treasury Bills can actually deliver a better after-tax return than CDs, despite their lower nominal yields. This is because Treasury Bill interest is exempt from state and local income taxes, while CD interest faces taxation at both federal and state levels. For someone in a state with a 6.5% tax rate or higher, that tax shield can make up for T-Bills’ lower headline rate, putting more money in your pocket when all taxes are considered. The question of which pays more after taxes is genuinely important—yet rarely discussed in personal finance conversations that focus only on advertised yields. Understanding this distinction can change how you allocate your short-term savings and money market funds.
Table of Contents
- How Treasury Bills and CDs Stack Up on Current Rates
- The State Tax Exemption That Changes Everything
- Calculating Your Real, After-Tax Returns
- Beyond Yield: Liquidity, FDIC Protection, and Opportunity Cost
- What Happens With Different Tax Brackets and States
- The Relationship Between T-Bills, Fed Policy, and Future Yields
- Which Wins and For Whom
- Conclusion
How Treasury Bills and CDs Stack Up on Current Rates
Treasury Bills are short-term obligations issued by the U.S. Department of the Treasury, typically with maturities of four weeks, thirteen weeks, and twenty-six weeks. The current rates reflect the market’s view of short-term interest rates and Fed policy. As of late April 2026, a 4-week T-Bill yields 3.65% while a 26-week T-Bill yields 3.68%—slightly higher due to the longer commitment. CDs, or Certificates of Deposit, are products offered by banks where you deposit money for a fixed term in exchange for a guaranteed rate of interest. The top rates available today reach 4.20% APY for a 9-month CD from Newtek Bank, and 4.15% APY for a similar 9-month term from Bread Savings.
These rates are notably higher than Treasury Bill yields, which is what makes the comparison interesting. Many people assume that higher yield automatically means a better investment, but that assumption breaks down when taxes enter the calculation. The gap between T-Bill yields and top CD rates is roughly 0.50% to 0.55%—meaningful enough that most savers would naturally gravitate toward CDs. However, this gap is also small enough that state tax considerations can completely reverse the advantage. For investors in lower-tax states or those with no state income tax, the CD rate is genuinely more lucrative. But for the rest of America’s savers, the comparison becomes far more interesting.
The State Tax Exemption That Changes Everything
This is the critical detail that most savers overlook. Interest earned on Treasury Bills is subject to federal income tax but entirely exempt from state and local income taxes. Interest earned on CDs, by contrast, is subject to taxation at both the federal and state levels. This structural difference is written into law and is not negotiable—it’s a permanent advantage built into Treasury Bills.
To understand the impact, consider that state income tax rates range from zero in states like Texas, Florida, and Nevada to nearly 14% in California. For someone in New York, the combined state and local tax rate on investment income can exceed 10%. When you layer a 10% state tax on top of the federal tax you’ll already pay on CD interest, the effective tax burden becomes substantially higher than what you face on Treasury Bill interest. The practical consequence is that a 4.20% CD yield doesn’t translate into a 4.20% after-tax return for most taxpayers. A person in the 24% federal tax bracket living in California would see their 4.20% CD yield reduced by roughly 0.60% to 0.70% just from combined federal and state taxes, bringing their after-tax yield closer to 3.50%—which is now below what a Treasury Bill provides.
Calculating Your Real, After-Tax Returns
Let’s work through a concrete example to make this tangible. Assume you’re investing $10,000 and you’re in the 24% federal tax bracket with a 6.5% state tax rate. This is a reasonable scenario for many middle-to-upper-income earners in states like Virginia, Illinois, or Colorado. With a 4.20% CD, your annual interest before taxes would be $420. Federal taxes take $100.80 (24% of $420), and state taxes take $27.30 (6.5% of $420). Your after-tax earnings are $292.90, or an effective after-tax yield of 2.93%.
With a 3.68% Treasury Bill, your annual interest would be $368. Federal taxes take $88.32 (24% of $368), leaving you with $279.68 after federal tax alone—and you pay nothing to your state. Your after-tax yield is 2.80%. This example shows that the CD still wins, but the gap has compressed from 0.52% in headline yield to just 0.13% in after-tax yield. Shift that scenario to California, where state tax on investment income reaches roughly 13.3%, and the math flips. The CD’s $420 in interest becomes $91.92 after federal taxes and $55.86 after state taxes, leaving you with just $272.22, or 2.72% after-tax yield. Now the Treasury Bill’s 2.80% after-tax yield wins.
Beyond Yield: Liquidity, FDIC Protection, and Opportunity Cost
Treasury Bills come with one significant limitation: they’re not deposit accounts and don’t carry FDIC insurance. However, they’re backed directly by the U.S. government, making them as safe as it gets from a credit perspective. The real trade-off involves liquidity. While you can sell a Treasury Bill before maturity on the secondary market, you may face a loss if interest rates have risen since purchase, and you’ll pay transaction costs. CDs, by contrast, lock your money in place for the full term.
If you need funds before maturity, you’ll face an early withdrawal penalty—typically ranging from a few months of interest on short-term CDs to three or six months of interest on longer-term products. For someone who values flexibility, this penalty can be meaningful. A $10,000 CD with a 6-month interest penalty on early withdrawal means you could lose $210 of your earnings, effectively wiping out the entire rate advantage. Treasury Bills mature within weeks or months, so you automatically get your principal back without any early-withdrawal concerns. This matters more than many savers realize. If your financial situation changes and you need access to the money, a T-Bill’s maturity schedule is a built-in escape hatch, while a CD requires accepting a penalty or negotiating with your bank.
What Happens With Different Tax Brackets and States
Your federal tax bracket is just as important as your state taxes. Someone in the 12% federal tax bracket will see a much smaller reduction in after-tax yield from CDs compared to someone in the 35% or 37% bracket. Conversely, someone living in a no-income-tax state like Texas faces no state tax headwind on either investment—yet Treasury Bills still come out slightly ahead when you factor in state and local taxes in other contexts. A warning worth stating plainly: if you’re in a lower tax bracket—say, 12% federal and in a state with minimal income tax—the CD rate will almost certainly provide a better after-tax return.
The after-tax advantage of Treasury Bills materializes specifically for people with meaningful state tax exposure. Failing to calculate your actual tax situation before choosing between these two investments is the most common mistake savers make. Additionally, tax-advantaged accounts like IRAs and 401(k)s change the entire equation. Within these accounts, Treasury Bills and CDs are taxed identically (either deferred or not at all, depending on the account type), so the state tax advantage of T-Bills disappears. In retirement accounts, the CD’s higher yield becomes the sole consideration, and you should chase the best rate available.
The Relationship Between T-Bills, Fed Policy, and Future Yields
Interest rates don’t stay constant. Treasury Bill yields rise and fall based on Federal Reserve policy and market expectations about inflation and economic growth. The rates available today—3.65% for 4-week bills—reflect the current Fed Funds rate environment. If the Fed cuts rates, these yields will decline, making the after-tax comparison against existing CDs locked in at 4.20% less favorable for Treasury Bills. However, it’s worth noting that CD rates adjust with the market over time as well.
When you renew a CD or open a new one, you’re facing current market rates—not a guaranteed perpetual return. If the Fed cuts rates by 1% later this year, you might be looking at CDs yielding 3.20% and T-Bills yielding 2.65%. In that scenario, the Treasury Bill strategy from today would have been well-timed, locking in rates before the decline. This uncertainty is precisely why calculating your after-tax returns right now, with current rates, gives you the most actionable picture. Markets change, but your state tax situation doesn’t shift monthly, so the advantage of Treasury Bills in high-tax states is somewhat more durable than it might initially appear.
Which Wins and For Whom
If you’re in the 12% or 22% federal tax bracket and live in a low-tax state, choose the CD. The 0.50% rate difference is substantial enough to outweigh the Treasury Bill’s tax advantage. If you’re in the 24% or 32% federal tax bracket and live in a high-tax state like California, New York, Maryland, or New Jersey, Treasury Bills likely win on an after-tax basis. The math works in favor of the tax-exempt interest, even though the headline rate is lower.
If you’re uncertain about your tax bracket, consult your most recent tax return or ask a tax professional—it’s worth the clarity. The broader insight is that safe, short-term savings should always be evaluated on an after-tax basis, never on yield alone. A 4.20% yield that becomes 2.72% after taxes is not genuinely better than a 3.68% yield that stays at 2.80% after taxes. By doing the calculation yourself, you ensure your money is working as hard as possible within your specific situation.
Conclusion
Treasury Bills and CDs both offer competitive, low-risk returns in the current interest rate environment. CDs show higher nominal yields—up to 4.20% APY versus 3.65% for 4-week Treasury Bills—but that headline difference is misleading once state taxes are factored in. For savers in high-tax states with meaningful federal tax exposure, Treasury Bills can deliver a superior after-tax return despite appearing less attractive on an advertised rate basis.
Your decision should rest on three calculations: your federal tax bracket, your state income tax rate, and your need for liquidity. Run the numbers with your actual tax situation, and the answer will become clear. If the math is close, consider your temperament around early access to funds—Treasury Bills provide more flexibility if your circumstances change mid-term. Either way, you’re choosing between two safe, respectable options, so the main risk is making the choice based on an incomplete picture of your after-tax reality.
