HYSA vs money market vs CD vs T-bills: the cash showdown

Cash you'll need within a few years shouldn't be in the stock market — but 'not in the market' still leaves four serious contenders: high-yield savings accounts, money market funds, certificates of deposit, and Treasury bills. They all feel similar (safe, boring, low single-digit returns), yet they differ meaningfully on access, rate behavior, taxes, and guarantees. Pick wrong and you can leave hundreds of dollars a year on the table, or worse, pay a penalty to reach your own emergency fund.

Here's the full head-to-head, then a winner for each scenario.

High-yield savings: the default

An online savings account paying 10–20x the big-bank average. FDIC insured, no minimums, transfers in a day or two. The catch: the rate floats at the bank's discretion, and banks quietly ratchet rates down on older customers while advertising teaser rates to new ones. If you haven't compared your rate in a year, check it — 'high yield' accounts drift into mediocrity constantly.

Money market funds: the yield chaser

Not to be confused with a bank's 'money market account,' a money market fund is a mutual fund holding ultra-short government and corporate debt. Yields typically run a bit above HYSAs and track market rates almost immediately — no bank deciding what to pass along. The trade-off: no FDIC insurance. Fund structures and regulation make major funds extremely safe, but 'extremely safe' and 'government guaranteed' are different sentences, and in 2008 one fund famously 'broke the buck.'

CDs: the rate lock

A CD trades access for certainty: you lock money up for 6 months to 5 years at a fixed rate, with an early-withdrawal penalty (commonly 3–12 months of interest). That's a bad deal for emergency funds — the whole point of which is access — but a great deal when rates are about to fall or when you need a known sum on a known date. When the Fed is cutting, a 12-month CD keeps paying its locked rate while every HYSA in America drifts down.

T-bills: the tax dodge

Treasury bills are short-term loans to the US government — 4 to 52 weeks — bought at a discount and paid back at face value. They carry the strongest guarantee available in dollars and one underrated superpower: the interest is exempt from state and local income tax. In a high-tax state, that exemption is worth real money, effectively boosting the yield versus a bank account paying the same headline rate.

Winner by scenario

The laddering trick

1. 1
   Split the pile

   Divide the cash you won't need immediately into 3–4 equal chunks.

2. 2
   Stagger the maturities

   Buy CDs or T-bills maturing at 3, 6, 9, and 12 months.

3. 3
   Roll as they mature

   When each rung matures, reinvest it at the far end of the ladder — or spend it if plans changed.

4. 4
   Enjoy both worlds

   You get locked rates on most of the money, plus a chunk coming free every quarter.

The bottom line

For most people the answer is boring: emergency fund in a HYSA, done. The other three earn their place as your cash grows — money market funds for brokerage cash, T-bills once state taxes bite or balances pass FDIC limits, CDs when you want to lock a rate for money with a date on it. Safe money should be simple money; pick the winner for your scenario and get back to your life.