Somewhere between residency and your first full attending year, a real cash pile forms: the emergency fund, the house down payment, the tax reserve for a , the quarterly bonus you have not allocated yet. For most physicians that pile reaches $50,000–$150,000 — and it usually sits wherever it landed, earning whatever the default account pays, which is frequently close to nothing. The three serious parking spots — the high-yield savings account, the money market fund, and the Treasury bill — all quote yields within about a percentage point of each other in mid-2026. The quoted yield is the least interesting difference among them. What actually separates the three is how the rate behaves when the Federal Reserve moves, how fast you can reach the money, what stands behind it if something fails, and — the one most physicians never price — how your state taxes the interest. This article compares all four dimensions properly, then hands you a decision table. The broader placement framework lives in the cash-parking module; this piece is the head-to-head.
One ground rule before the numbers: every yield in this article is a snapshot. Rates cited here are from the first two weeks of July 2026 and will be wrong — in one direction or the other — by the time you read this. The relationships between the three vehicles are what persist.
The HYSA: insured and instant, but the bank sets the rate
A high-yield savings account is a bank deposit. As of July 2026, top-of-market accounts in the major rate surveys pay roughly 4.0%–4.5% APY, while the national average savings rate across all banks sits near 0.38% — a spread that tells you the "high-yield" label is about which bank you chose, not about the product category.
Three properties define the HYSA:
- Backing: FDIC insurance covers up to $250,000 per depositor, per bank, per ownership category — dollar-for-dollar, principal plus accrued interest. This is the strongest consumer guarantee in American finance short of the Treasury itself. A married couple using individual and joint account categories at one bank can cover $1,000,000; a physician with more cash than that at a single bank has a structural problem, not a yield problem.
- Access: same-day to next-day. Transfers to a linked checking account typically clear in one business day, and there is no sale, no settlement, and no price.
- Rate behavior: the rate is administered — the bank changes it whenever it chooses, with no notice and no formula. When the Federal Reserve cuts, competitive banks often reprice within days, sometimes in anticipation. When the Fed hikes, the same banks are noticeably slower on the way up. The 4.5% headline that recruited you carries no promise about next quarter, and survey data from June–July 2026 shows the drift: of the accounts that changed rates in that window, three-quarters moved down.
The HYSA also carries the only behavioral trap of the three: teaser structures. The highest advertised APYs frequently require direct deposits, balance caps, or activity hoops, and the rate you actually earn after the promotional window is the number that matters.
The money market fund: the yield tracks the Fed, and the "insurance" is different in kind
A money market fund is not a bank account. It is a mutual fund — typically held at a brokerage — that owns a rolling portfolio of very short instruments (Treasury bills, repurchase agreements, agency paper) and passes the portfolio's yield through to you. As of the week ended July 2, 2026, the most widely tracked index of the 100 largest taxable money funds averaged a 3.47% seven-day yield, with the bulk of funds between 3.0% and 4.0%.
The three properties, contrasted:
- Backing: there is no FDIC insurance. SIPC protection at the brokerage covers up to $500,000 (including $250,000 in cash) — but read what it covers: the custody of your assets if the brokerage itself fails, not the value of the fund. Government money market funds hold Treasury and agency paper and transact at a stable $1.00 share price, which they have defended through every modern stress event — but the $1.00 is an objective, not a guarantee, and the distinction is worth one honest sentence: you are an investor here, not a depositor.
- Access: one step slower than a savings account. You sell shares (same day), the sale settles (next business day), and then the cash transfers to checking if it is not already at the brokerage where your bills are paid. Call it one to three business days door to door.
- Rate behavior: nearly mechanical. The fund's yield is the weighted average of paper maturing in days to weeks, so when the Fed moves, the seven-day yield follows over roughly two to six weeks as holdings roll — up and down with equal speed, no discretion involved. A money market fund never quietly stops being competitive the way a bank account can, because there is no marketing department between you and the yield.
Why does the average money fund trail the top HYSA by roughly half a point in July 2026? Because the comparison is average-to-best. Top HYSA rates are recruitment pricing by hungry banks; the money fund is the market rate minus a 0.1%–0.4% expense ratio, no hoops attached. Whether the HYSA premium survives your particular bank's next repricing is exactly the uncertainty you cannot resolve in advance.
The T-bill: a state-tax discount backed by the Treasury itself
A Treasury bill is a direct obligation of the United States, sold at a discount and repaid at face value in 4 to 52 weeks. In June–July 2026 auctions, bills across the 4-week to 26-week range yielded roughly 3.5%–3.75%; the 4-week bill stood at 3.69% on July 13, 2026.
- Backing: the full faith and credit of the United States — not an insurance fund that pays after a failure, but the direct promise of the borrower that also prints the currency. There is no coverage limit. This is the reference point every other guarantee is measured against.
- Access: the weakest of the three, and honestly so. Held to maturity, a bill returns exactly face value on a known date. Sold early through a brokerage, it fetches the market price, which can be a hair above or below what you paid, plus settlement and transfer time. Bills purchased directly through the government portal must be transferred to a broker before an early sale, which takes weeks. Treat a bill as money with an appointment.
- Rate behavior: locked at purchase. The yield you buy is the yield you get to maturity, regardless of what the Fed does the following week. A ladder of staggered maturities converts this from a bug into a feature: something matures every few weeks at whatever the new market rate reinvests at.
Then there is the feature that does not appear on any yield board. Under 31 U.S.C. § 3124, interest on Treasury obligations is exempt from all state and local income taxation — an exemption that bank interest and most money-fund income do not share. For a physician in a no-income-tax state this is worth nothing. For everyone else it is a silent yield bonus that scales with your state bracket:
Example calculation
Assumptions, stated explicitly: attending in a state with a flat 5% income tax; $60,000 parked for a full year; HYSA at 3.90% APY versus a 26-week T-bill strategy at 3.70% (both figures July 2026, per the surveys and auction results cited above); the state tax produces no offsetting federal benefit because the SALT deduction is already capped for this taxpayer.
- HYSA interest: $60,000 × 3.90% = $2,340
- State tax on it: $2,340 × 5% = $117
- HYSA after state tax: $2,223 → effective 3.71%
- T-bill interest: $60,000 × 3.70% = $2,220; state tax: $0 → effective 3.70%
- Taxable-equivalent yield of the 3.70% bill: 3.70% ÷ (1 − 0.05) = 3.89%
A 20-basis-point HYSA advantage evaporates at a 5% state rate. In a 9% state, the same bill is equivalent to a 4.07% bank rate, and the T-bill wins outright.
Key insight
When the Fed cuts, your three parking spots reprice at three different speeds: the HYSA moves whenever the bank decides (often immediately, sometimes pre-emptively), the money fund glides down over two to six weeks as its paper rolls, and the T-bill you already own does not move at all until maturity. In a falling-rate environment, this ordering quietly reverses the July 2026 league table — which is precisely why you should own the structure that fits your need for the money, not the vehicle that tops this month's survey.
Match the vehicle to the job, not to the highest headline yield
| Dimension | HYSA | Money market fund | Treasury bills |
|---|---|---|---|
| Yield, July 2026 (dated) | ~4.0–4.5% APY at the top of surveys; 0.38% national average | ~3.47% average 7-day yield (100 largest funds, 7/2/2026) | ~3.5–3.75% at auction (June–July 2026) |
| How the rate moves | Bank discretion, no notice | Tracks the Fed within 2–6 weeks, both directions | Fixed to maturity; ladder to stay current |
| Access | Same/next business day | 1–3 business days | At maturity, or early sale at market price |
| Backing | FDIC, $250,000 per depositor per bank per category | SIPC custody coverage only; $1.00 NAV is an objective, not a guarantee | Full faith and credit of the U.S., no limit |
| State income tax on interest | Fully taxable | Taxable except the pass-through Treasury share | Exempt (31 U.S.C. § 3124) |
| Wins when | You need same-day money and will police the rate | You want market yield with zero maintenance at the brokerage you already use | You live in a taxed state, or the amount exceeds comfortable FDIC coverage |
Important
Every yield in this table is a July 2026 snapshot, not a property of the product. Do not choose a vehicle because of a 40-basis-point gap in this table read months later; the gaps move, and in a Fed cutting cycle they invert. The backing, access, and state-tax rows are the durable facts.
Your emergency fund wants tiers, not a single account
The comparison stops being theoretical the moment you apply it to the one cash pile every physician must hold. A three-to-six-month emergency fund — commonly $30,000–$90,000 at attending expenses — does not need to be uniformly liquid, because emergencies do not consume six months of expenses in a single day. A structure that respects that:
- Tier 1 — first month of expenses in the HYSA: same-day money for the deductible, the flight, the car transmission.
- Tier 2 — the remaining months in a money market fund or a short T-bill ladder: reachable in days, earning the market rate (and state-tax-free in the ladder), invisible enough to stop tempting you.
How many months belong in each tier depends on your disability coverage, contract terms, and household structure — the sizing logic is worked through in the emergency-fund design module. And once the fund is full, the same three-vehicle comparison governs every other dollar waiting for a purpose, from tax reserves to the down payment; where physician cash should live extends the map to those piles.
Quick takeaway
All three vehicles are legitimate; none is best at everything. The HYSA buys speed and FDIC certainty at the price of rate policing. The money fund buys market yield with no maintenance at the price of depositor status. The T-bill buys the strongest backing in existence plus a state-tax exemption at the price of an appointment with your own money. Tier the emergency fund across them, quantify your state-tax bonus before comparing headline yields, and re-read the yields as history, not fact.
Common questions
Is a money market fund the same as a money market account?
No, and the naming collision causes real mistakes. A money market account is a bank deposit with FDIC insurance, functionally an HYSA with checks. A money market fund is a brokerage investment with SIPC custody protection and no deposit insurance. Before parking six figures, confirm which one you actually hold.
Can I lose money in a T-bill?
Held to maturity: no, in nominal terms — you receive face value from the Treasury on the stated date. Sold before maturity: possibly, slightly, if rates rose after your purchase and the market price of your bill dipped. For bills of 26 weeks or less the fluctuation is small, but it is not zero, which is why money you may need on 48 hours' notice belongs in Tier 1 instead.
Do I owe state tax on money market fund income?
Partly. Funds that hold Treasury securities pass the state-tax exemption through in proportion to their Treasury holdings, reported each January. A fund holding mostly repurchase agreements passes through little; several states also impose a minimum Treasury percentage before allowing any exemption. If the state-tax feature is why you are choosing the vehicle, direct bills are the clean version of the trade.
Is a 4.5% account with hoops better than a 3.7% bill without them?
Price the hoops and your state. At 5% state tax, the 4.5% deposit nets about 4.28% — still ahead of a 3.70% bill, if you genuinely clear the direct-deposit and balance-cap requirements every month and the rate survives past the promotional window. The gap that looks like 80 basis points on the billboard is often 20–40 in practice, and it is rented, not owned.
What to do next
- Look up the current rate on the account where your cash sits today — the actual rate on your balance, not the advertised one. Two minutes, and it is frequently the most expensive number in this article.
- Find your state's marginal income tax rate and compute your personal T-bill bonus: quoted bill yield ÷ (1 − state rate).
- Size your emergency fund with the design framework, then split it: one month of expenses in the HYSA, the remainder in a money fund or 8–13–26 week bill ladder.
- If any single bank holds more than $250,000 of your cash in one ownership category, restructure this week — that is uncompensated risk with a free fix.
- Put a twice-yearly reminder on the calendar to re-compare the three yields, because the July 2026 numbers in this article are already history.
The parking decision is deliberately boring, and boring is the point: cash exists so the rest of the plan never has to be sold on a bad day. Get the structure right once, automate the flows, and spend your attention where the compounding actually happens. This is education, not individualized financial advice.