If your cash is sitting in a savings account earning next to nothing, two upgrades dominate the conversation: Treasury bills and certificates of deposit (CDs). Both are safe, both usually beat savings accounts, and both have trade-offs most comparisons gloss over. Here’s the honest breakdown.
Yield: usually close, but check the details
In normal markets, T-bills and CDs of similar maturity yield within shouting distance of each other. Banks set CD rates to compete for deposits; T-bill rates are set by auction and track the Fed closely. Right now, compare the actual numbers, and don’t assume one always wins. (If the rate landscape confuses you, our high-rate vs. investment-rate explainer breaks down what banks mean by “high yield.”)
Taxes: T-bills win in high-tax states
This is the biggest structural difference. T-bill interest is exempt from state and local income taxes; CD interest is fully taxable at every level. In a high-tax state, a T-bill yielding 4.5% beats a CD yielding 4.7% after tax. In a no-income-tax state, the advantage disappears, so compare on yield alone.
A worked example: the after-tax math
Take $50,000 in California, where the top state income tax rate is 9.3%. A T-bill yielding 4.5% earns $2,250 in a year, and you keep all of it after state tax. A CD yielding 4.7% earns $2,350, but the state takes 9.3%, or $218.55, leaving $2,131.45. The T-bill wins by about $119 a year despite the lower headline yield. Flip it to Texas, which has no state income tax, and the CD wins by $100. The lesson: never compare headline yields across state lines without doing the after-tax math for your own state.
How to actually buy each one
T-bills come in 4, 8, 13, 17, 26, and 52-week maturities. You can buy them through a brokerage account (the easiest route if you already have one) or directly at TreasuryDirect. Our guide to buying Treasury bills walks through both. CDs are simpler: open one at any bank or credit union, pick a term from 3 months to 5 years, and deposit. Brokered CDs, sold through brokerages, sometimes offer better rates than your local bank, so shop around before you lock in.
Liquidity and penalties
T-bills win here too. You can sell a T-bill on the secondary market any time (at the market price, which can move). CDs typically lock your money up. Break one early and you pay a penalty, often several months of interest. If there’s any chance you’ll need the cash, T-bills are more flexible. Laddering either one smooths out the reinvestment question.
Safety: both are rock-solid
CDs are FDIC-insured up to $250,000 per depositor per bank. T-bills are backed by the U.S. Treasury, the textbook definition of risk-free. For practical purposes, both are safe; just keep CDs under the FDIC limit per bank.
The laddering trick
Instead of putting all your cash in one 12-month CD or one 52-week T-bill, split it into rungs. For example, divide $30,000 into three $10,000 chunks: a 3-month, a 6-month, and a 9-month maturity. As each rung matures, roll it into a new 9-month rung. You get regular access to a third of your cash every three months, and if rates rise, your maturing rungs capture the higher yield quickly. Laddering works for both T-bills and CDs, and it’s the simplest way to balance yield with flexibility.
Three mistakes people make with cash
First, chasing the headline CD rate without doing after-tax math. A 5.0% CD in California can lose to a 4.7% T-bill once state tax is applied. Second, locking emergency-fund money in a long CD. Your emergency fund needs to be accessible; a 5-year CD with an early-withdrawal penalty defeats the purpose. Keep emergency cash in a high-yield savings account or short T-bills, and use CDs or longer T-bills only for money you truly won’t need. Third, ignoring the reinvestment question. When a CD or bill matures, have a plan: auto-roll it, ladder it, or move it. Cash that sits in a 0.01% settlement account after maturity is cash earning nothing.
The verdict
For most people with cash to park: T-bills if you’re in a high-tax state or value flexibility; CDs if you find a rate that beats T-bills after tax and you won’t need the money early. Either one beats a savings account.
Winchell House 
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