The Money Leak Nobody Notices
You’ve got $50,000 sitting in the checking account attached to your regular bank. Not because you decided to keep it there. It just accumulated: a bonus landed, a bill didn’t come due, a transfer you meant to make got put off for six weeks and then six months. Meanwhile that account is paying something like 0.01% APY, which on $50,000 comes out to $5 a year. Move that same $50,000 into a high-yield savings account at 4%, and it earns $2,000 a year instead. Same money. Same risk. $1,995 difference, every single year, for doing nothing except moving it.
That’s the most common and most fixable leak in a high earner’s finances. Not a bad investment. Not an overpriced fund. Just cash parked in the wrong place because nobody made a decision about it.
This isn’t complicated once you know the menu. Here’s where short-term cash should actually live, broken down by what you’re saving for and how soon you need it.
High-Yield Savings Accounts: The Default
A high-yield savings account (HYSA) at an online bank, think Ally, Marcus, SoFi, Capital One 360, is FDIC insured up to $250,000 per depositor per bank per ownership category, and the money is available in a transfer or two. No lockup, no penalty, no waiting for a bond to mature.
The tradeoff: the rate isn’t fixed. It floats with whatever the bank feels like paying, which itself tracks the broader interest rate environment. If rates fall, your HYSA rate falls with them, usually within a billing cycle or two, and there’s no notice period. You don’t get a heads up email that says “hey, we’re cutting your rate next Tuesday.” You just log in one day and it’s lower.
That volatility is fine for a fund you might need on short notice, which is exactly the profile of an emergency fund. You’re not trying to lock in today’s rate for the next two years. You’re trying to keep money liquid and earning something better than a checking account while it waits to be needed.
For any dollar figure in this article, treat the rate as an assumption, not a promise. I’ll use 4% to 4.5% as round numbers because they’re easy to do math with, not because that’s what your bank pays today. Check the actual number before you make a decision.
Money Market Funds: Convenient, With a Catch
If your cash sits inside a brokerage account (Fidelity, Schwab, Vanguard), it’s probably parked in a money market fund, either automatically as the account’s settlement fund or by your own choice. These funds hold short-term, high-quality debt and aim to keep a stable $1 share price while paying out a floating yield, similar in spirit to a HYSA.
The convenience is real: money already sitting there earns a return without you doing anything, and moving it into a stock or ETF purchase takes seconds instead of a bank transfer.
The catch people miss: there are two different flavors, and they carry different risk.
- Government money market funds hold Treasury bills, repurchase agreements backed by Treasuries, and similar government debt. These are about as safe as short-term cash gets.
- Prime money market funds hold commercial paper and other corporate short-term debt, chasing a slightly higher yield in exchange for slightly more credit risk. In September 2008, a prime fund (the Reserve Primary Fund) “broke the buck,” meaning its share price dropped below $1, because it held Lehman Brothers debt when Lehman collapsed. That’s a rare, extreme event, but it’s the reason the distinction exists at all.
For an emergency fund or short-term cash, default to the government fund at your brokerage, not the prime one. The yield difference is usually small; the risk difference, in a genuine crisis, is the whole point of holding cash in the first place.
Money market funds are not FDIC insured. They’re covered by SIPC, which is a different kind of protection entirely (more on that below).
Treasury Bills: The State-Tax Angle
A Treasury bill (T-bill) is a short-term IOU from the US government, sold at a discount and paying face value at maturity, with terms ranging from four weeks out to 52 weeks. You can buy them directly at TreasuryDirect or through a regular brokerage account, where they trade almost as easily as a stock.
The structural fact that matters here: interest from T-bills (and other Treasury securities) is exempt from state and local income tax. It’s still taxed federally, just not by your state. A HYSA or a prime money market fund gives you no such break. Every dollar of interest gets taxed at both the federal and state level, the same as your paycheck.
That distinction is worth real money if you live somewhere with a real state income tax, and worth nothing if you don’t. Here’s the actual comparison, using a 4.5% nominal yield on both a HYSA and a T-bill for a fair fight, someone in the 32% federal bracket, and $50,000 parked in cash:
California (9.3% state tax on top of 32% federal):
- HYSA after-tax income: $1,320.75/year
- T-bill after-tax income: $1,530.00/year
- T-bill advantage: $209.25/year, on the same $50,000, at the same nominal yield
Texas or Florida (no state income tax):
- HYSA after-tax income: $1,530.00/year
- T-bill after-tax income: $1,530.00/year
- T-bill advantage: $0
If you live in California, New York, or another high-tax state, T-bills are quietly worth more than a same-yield HYSA. If you live in Texas, Florida, Washington, or another no-income-tax state, the state exemption buys you nothing and you should just compare raw yields.
The tradeoff for that tax break is liquidity. A T-bill you bought last month isn’t available until it matures, unless you sell it on the secondary market, which you generally can, but it adds a step a HYSA withdrawal doesn’t have. Laddering solves that by staggering maturities.
Building a T-Bill Ladder
A ladder solves the liquidity problem by staggering maturities so something is always coming due soon.
Say you want $30,000 in T-bills instead of one lump sitting in a HYSA. Instead of buying one 26-week bill, split it three ways:
- $10,000 in a 4-week bill
- $10,000 in an 8-week bill
- $10,000 in a 13-week bill
Every few weeks, something matures. You either spend it if you need it, or roll it into a new bill at the back of the ladder. After the first round, you’ve effectively got cash coming free on a rolling schedule, all while collecting the state-tax exemption, without giving up meaningful access to the money. It takes a bit more setup than a HYSA (you’re placing a handful of orders instead of one), but once it’s running, it mostly runs itself.
Short-Term Treasury ETFs
If a ladder sounds like more account management than you want, a short-term Treasury ETF (like SGOV or BIL, which hold T-bills maturing in roughly 0 to 3 months) gets you close to the same exposure in one ticker. Buy it like a stock, sell it like a stock, and the underlying bills roll over automatically inside the fund.
You give up a little of the precision of a hand-built ladder, and technically the ETF’s own dividend treatment can differ slightly from holding T-bills directly, but for most people the simplicity is worth it. If you already have a brokerage account and don’t want to babysit individual bill purchases, this is the practical middle ground between a money market fund and a full ladder.
CDs: Usually the Wrong Tool for This Job
A certificate of deposit (CD) locks your money for a fixed term, usually anywhere from 3 months to 5 years, in exchange for a fixed rate. That fixed rate can be attractive when it’s higher than what a HYSA is paying, and for money you know you won’t touch, that’s a real advantage over the HYSA’s floating rate.
The problem is the early withdrawal penalty, and it’s worse than people expect. A common structure on a 12-month CD is a penalty equal to 3 months of interest if you cash out early. On a $20,000 CD paying 4.5%, that’s $900 in annual interest, or $75 a month, so pulling out early costs you $225, straight out of your principal in some cases, not just forfeited future interest.
For an emergency fund, that’s exactly backwards. The entire point of the fund is that you don’t know when you’ll need it. A CD bets that you do. If your car transmission dies in month four of a 12-month CD, you’re paying a penalty to access money that was supposed to be there for exactly this situation.
CDs make sense for money with a known, fixed use date, a wedding deposit due in 14 months, a tax bill you know is coming, where the fixed rate and the fixed timeline actually match up. They’re a poor fit for the “I don’t know when I’ll need this” bucket, which is most of what people are trying to solve when they ask this question in the first place.
FDIC vs SIPC vs “Backed by Treasuries”
Three different protections get talked about like they’re interchangeable. They’re not.
FDIC insurance covers bank deposits (checking, savings, HYSAs, CDs) up to $250,000 per depositor, per bank, per ownership category. That means a single person can have $250,000 insured in an individual account and another $250,000 insured in a joint account at the same bank, because those are different ownership categories. It protects you if the bank itself fails. It has nothing to do with market risk, there isn’t any in a savings account.
SIPC coverage applies to brokerage accounts, up to $500,000 total, including a $250,000 sublimit for cash. It protects you if the brokerage itself fails and your assets go missing or can’t be returned, not if your investments lose value. If your money market fund or ETF drops in price because of normal market movement, SIPC does nothing for you, and it isn’t supposed to.
“Backed by the full faith and credit of the US government” describes Treasury securities themselves (T-bills, notes, bonds), not an insurance program at all. There’s no dollar cap, because the claim is that the US government will pay it back, not that a fund exists to reimburse you if a middleman fails. That’s a different kind of guarantee than FDIC or SIPC, resting on the government’s ability and willingness to pay its own debt rather than reimbursement from an insurance fund.
The confusion happens because all three get described casually as “cash is safe here,” and they use similar-sounding language. FDIC is deposit insurance against bank failure. SIPC is asset insurance against brokerage failure. Treasuries are a direct promise from the government, with no failure scenario involving a third-party insurer at all.
Your Actual Default by Bucket
Stop overthinking this and match the account to the timeline.
Emergency fund (need it anytime, no notice): HYSA. This is the right default, no asterisks. Instant-ish access, FDIC insured, and the rate volatility barely matters because you’re not trying to lock in a rate for years, you’re trying to have the money the day you need it. If you’re in a high-tax state and want a bit more yield, a short T-bill ladder or a short-term Treasury ETF works too, just keep enough in the HYSA to cover the first few weeks so you’re never waiting on a maturity date to cover a real emergency.
Known expense in 6 to 18 months (down payment gap, a planned move, a big known bill): This is T-bill or short-term Treasury ETF territory, especially in a high-tax state where the exemption is doing real work. A short ladder timed loosely around when you expect to need the money gives you a bit more yield than a HYSA with only a little less flexibility. A CD can work here too, if the term lines up with your timeline and you’re confident you won’t need the money early.
House down payment 2 to 3 years out: Still not the stock market. A 30% drop in the two years before you need a down payment is a real scenario, not a tail risk, and it’s exactly the wrong time to discover that. A longer T-bill ladder, a short-term Treasury ETF, or a mix of HYSA and T-bills for the closer-in portion all work. The goal at this horizon isn’t maximum yield, it’s making sure the money is actually there when the offer gets accepted.
The One-Sentence Version
If you take nothing else from this: check what your cash is actually earning right now, today, and if it’s sitting in a big-bank checking or savings account at a fraction of a percent, move it. Everything else, HYSA vs money market vs T-bill ladder vs short-term Treasury ETF, is optimization on top of a decision you should already have made. Getting from 0.01% to 4% is worth $1,995 a year on $50,000. Getting the state-tax angle right on top of that is worth a couple hundred more. Both are better use of an afternoon than another hour comparing brokerages.
