The 4.50% Account Beat the 4.60% One. Here Is Why.
Comparing cash accounts on their advertised rate ignores the one factor that changes the ranking: how each is taxed. On $25,000, the lowest-rate option finished ahead by $112.50 a year.
You have $25,000 that needs to stay safe and reachable. Three options are on the table: a high-yield savings account at 4.25%, a twelve-month CD at 4.60%, and a twelve-month Treasury bill at 4.50%. The CD advertises the highest rate, so the CD wins.
It does not. For anyone living in a state with income tax, the Treasury bill finishes ahead, and by a wider margin than the rate gap suggests.
The comparison after tax
Interest from savings accounts and CDs is taxed as ordinary income at both the federal and state level. Interest from Treasury securities is taxed federally but is exempt from state and local income tax. That exemption is the whole story.
| High-yield savings | 12-month CD | 12-month T-bill | |
|---|---|---|---|
| Advertised rate | 4.25% | 4.60% | 4.50% |
| Gross interest | $1,062.50 | $1,150.00 | $1,125.00 |
| Federal tax at 22% | $233.75 | $253.00 | $247.50 |
| State tax at 6% | $63.75 | $69.00 | $0.00 |
| Net interest | $765.00 | $828.00 | $877.50 |
| Effective after-tax yield | 3.06% | 3.31% | 3.51% |
The T-bill returns $877.50 against the CD's $828.00, a difference of $49.50, despite advertising a rate one tenth of a point lower. Against the savings account the gap is $112.50. The ranking by advertised rate and the ranking by money you keep are simply different lists.
What each instrument is actually for
High-yield savings
The right default for money you might need without warning. Federally insured up to the standard limit, no fixed term, no penalty for withdrawal, and accessible within a day or two. The trade-off is that the rate is variable and the bank can lower it whenever it likes, usually within days of a central bank rate cut and considerably more slowly after an increase.
Certificates of deposit
You lock the money for a fixed term in exchange for a fixed rate. The rate is guaranteed for the full term, which is genuinely valuable when rates are expected to fall. The cost is liquidity: early withdrawal typically forfeits three to six months of interest, and on a short CD that can exceed everything you earned.
The standard fix is a ladder. Split the money across CDs maturing at staggered intervals, for example five equal tranches at one through five years. Each year one matures, giving you access to a fifth of the balance without penalty while the rest continues earning longer-term rates.
Treasury bills
Short-term debt issued by the federal government, sold at a discount and redeemed at face value, with the difference being your return. Backed by the full faith and credit of the U.S. government rather than by deposit insurance, which means there is no balance limit on the guarantee. They can be bought directly from the Treasury or through a brokerage, and they trade on a secondary market if you need to exit early.
The state tax exemption makes them the strongest option for larger cash balances in high-tax states. The practical downsides are that buying them takes more effort than opening a savings account, and selling before maturity exposes you to a small amount of price risk.
Choosing between them
| If you need | Use |
|---|---|
| Access within days, no fixed horizon | High-yield savings |
| A known date and a locked rate | CD, or a CD ladder |
| Best after-tax yield in a high-tax state | Treasury bills |
| A balance above deposit insurance limits | Treasury bills |
| Simplicity above all | High-yield savings |
For most people the honest answer is that a high-yield savings account is good enough, and the difference between the options at these balances is smaller than the difference between saving and not saving. The comparison becomes worth the effort somewhere above roughly $25,000, or sooner if your state tax rate is high.
Two things that quietly erode the return
Introductory rates are the most common trap. Some accounts advertise a headline rate that applies for three or six months, or only to balances below a threshold, then revert to something unremarkable. Check whether the rate is promotional, whether it is tiered, and whether it applies to your whole balance.
Inflation is the other. At 3% inflation, an account paying 4.25% is preserving purchasing power with 1.25 points to spare before tax, and after the 28% combined tax rate used above it is roughly breaking even. This is the strongest argument for keeping only what you genuinely need in cash and investing the rest, and it applies regardless of which of these three you choose.
Compare CD terms and yieldsCD CalculatorProject a savings balance over timeSavings CalculatorFrequently asked questions
Are Treasury bills really safer than an insured savings account?
Both are about as safe as financial instruments get, but the guarantees differ in structure. Deposit insurance covers up to a set limit per depositor, per institution, per ownership category. Treasury securities carry the direct backing of the federal government with no cap. For balances below the insurance limit the practical difference is negligible. Above it, Treasuries avoid the need to spread money across multiple banks.
What happens if I need my CD money early?
You pay an early withdrawal penalty, typically three months of interest on terms up to a year and six months or more on longer terms. Some institutions offer no-penalty CDs at a slightly lower rate, which can be a reasonable middle ground. Read the penalty terms before opening, since they vary considerably and are the main risk of the product.
Is APY the right number to compare?
For savings accounts and CDs, yes. APY already incorporates compounding frequency, so it reflects what you actually earn over a year and is directly comparable across institutions. Treasury bills are quoted differently, as a discount rate or an investment rate, so converting to a comparable annualised figure takes an extra step. Whichever you use, apply the same tax treatment to all of them before ranking, which is the step most comparisons skip.
Does this change if I hold these inside a retirement account?
Substantially. Inside a tax-deferred or tax-free account there is no annual tax on the interest, so the Treasury state tax exemption provides no benefit at all. In that setting you should simply take the highest yield, which in this example is the 4.60% CD. Tax-advantaged accounts are generally a poor place for cash regardless, since the tax shelter is more valuable applied to assets with higher expected returns.
How often should I move money chasing a better rate?
Less often than the rate comparison sites suggest. On $25,000, a 0.25 point improvement is $62.50 a year before tax, which is worth perhaps one transfer but not quarterly attention. What is worth doing is checking annually that your account has not quietly fallen well behind the market, which happens routinely as banks stop passing on rate increases to existing customers while advertising better rates to new ones.
Disclaimer: This article is educational and does not constitute financial, investment, tax, or legal advice. Figures are illustrative and computed from the assumptions stated in the article; your own situation will differ. Verify any decision with a qualified professional before acting on it.