Cash management.
Where to keep money you are not investing.

The five cash vehicles, side by side

The five options cluster tightly: the best widely available HYSA pays about 4.27% APYAnnual Percentage Yield (APY)An annualized measure of deposit interest that includes the effect of compounding. It is not an inflation-adjusted or after-tax return.Full definition, a government money-market fund like SPAXX about 3.5%, and T-bills and CDs of a year or less about 4.0% to 4.5%, as of mid-October 2026. You are choosing between a 4.3% and a 3.5%, not a 4% and an 8%.

Yields are ranges, not quotes, and every one tracks the federal funds rate. The spreadSpreadThe gap between two prices or rates. In trading, it is the difference between the price buyers pay (ask) and the price sellers get (bid). Many Bitcoin apps and money-transfer services also build a markup into the price they quote you, a cost on top of the advertised fee even when that fee is $0.Full definition from best to worst among the four real options is under a percentage point, which is why chasing the last basis point is rarely worth the effort. Run your own after-tax and after-inflation numbers in the real return calculator and the money-market after-tax tool.

How much should sit in cash at all?

Enough to cover real emergencies and known near-term spending, and not a dollar more. The standard frame is three to six months of essential expenses in liquid cash, more if your income is variable or your job is at risk. Everything past that plus your known-date spending (a car, a down payment, a tax bill) is what these five vehicles are for.

Beyond the emergency fund and dated needs, holding cash is a drag, not a cushion. At a real return near zero, a large idle balance quietly loses purchasing powerPurchasing powerWhat money can actually buy, not the number on the bill or in the account. Inflation shrinks it over time: by the BLS consumer price index, it takes more than $8 today to buy what $1 bought in 1971. Same dollar, much less buying ability.Full definition every year. Size the buffer with the emergency fund calculator.

Section 1 · The hierarchy of cash placement

Not all cash serves the same purpose. Before choosing where to put it, determine what it is for.

Emergency fund (3-6 months of expenses)

• Needs: immediate access, no loss of principal, some yield.
• Best fit: HYSA or money market fund at Fidelity (SPAXX or FZFXX).
• Not: CDs (early withdrawal penalty), T-bills (require selling on secondary market), investment accounts (can be down when you need the money).

Short-term savings (3-12 months)

• Use case: a trip, a car, a down payment in the next year.
• Best fit: T-bills or CDs maturing near the target date. Money market fund works too.

Medium-term savings (1-5 years)

• Use case: down payment in 2-3 years.
• Best fit: T-bill ladder, short-durationdurationA measure of how sensitive a bond price is to interest rate changes. A bond with 10-year duration falls roughly 10% in price when rates rise 1 percentage point. Longer duration = more interest rate risk. bond fund, or I-bonds (under the $10K/year limit).
• Not: stocks (too volatile for a known near-term need).

Long-term savings (5+ years)

• Use case: retirement, financial independence.
• Best fit: invested in low-cost index funds or Bitcoin allocation. See Index Funds and the Three-Fund Portfolio and How Much Bitcoin Should You Own?.
• Not: cash or money market funds. The real return on cash is approximately zero after inflation over time.

Section 2 · Money market funds, compared

A money market fund (MMF) is a mutual fund that holds ultra-short-term, high-quality debt: government securities, commercial paper, repurchase agreements.

It is not a money market account at a bank (those are FDIC-insured, typically lower yield). It is not invested in stocks or bonds. It is not FDIC-insured: FDIC deposit insurance covers deposits only, up to $250,000 per depositor, per insured bank, for each account ownership category, and a money market fund is not a deposit. Like any mutual fund, it is not guaranteed or insured by the FDIC or any other government agency verify×DON'T TRUST, VERIFYClaim: FDIC deposit insurance covers $250,000 per depositor, per insured bank, for each account ownership category. It covers deposits only. Money market funds, like all mutual funds, are not guaranteed or insured by the FDIC or any other government agency.Verify at: FDIC: What We Do (Deposit Insurance) ↗ · SEC Investor.gov: Money Market Funds bulletin ↗ · SEC Investor.gov: Mutual Funds ↗ Source 2 in the list belowfdic.gov: the FDIC insures deposits only, not securities, mutual funds or other investments. The SEC's investor bulletin: money in a money market fund, like money in any mutual fund, is not guaranteed by the FDIC, while a bank money market deposit account is, up to the limits. Investor.gov's mutual fund page: mutual funds are not guaranteed or insured by the FDIC or any other government agency.. A fund held at a brokerage that is a SIPCSecurities Investor Protection Corporation (SIPC)When a member brokerage firm fails and customer assets are missing, most customers are protected up to $500,000, including $250,000 for cash. It does not cover a drop in a fund's value or any other market loss, and money market mutual funds count as securities, not cash. member gets a different protection, and sipc.org says it is not the same as protection for cash at an FDIC-insured bank: if a member brokerage firm fails and assets are missing from customer accounts, SIPC works to restore them, up to $500,000, including $250,000 for cash. SIPC treats money market fund shares as securities and does not cover a drop in the fund's value verify×DON'T TRUST, VERIFYClaim: SIPC protection is limited to $500,000, including a $250,000 limit for cash. It applies when a member brokerage firm fails and customer assets are missing. It is not the same as protection for cash at an FDIC-insured bank, and it does not protect against a decline in the value of securities, money market mutual funds included.Verify at: SIPC: What SIPC Protects ↗ Source 3 in the list belowSIPC's page states that the $500,000 limit includes the $250,000 cash limit, that SIPC protects only the custody function of the broker-dealer, that SIPC protection is not the same as protection for cash at an FDIC-insured bank, that it does not protect against the decline in value of securities, and that money market mutual funds are protected as securities..

SPAXX (Fidelity Government Money Market Fund)

• Holds: US government securities and repurchase agreements.
• 7-day yield as of October 15, 2026: 3.50% verify×DON'T TRUST, VERIFYClaim: SPAXX 7-day yield was 3.50% as of October 15, 2026.Verify at: Fidelity SPAXX page ↗ Source 4 in the list belowYields change weekly. Tracks short-term Fed-influenced rates..
• Expense ratioExpense ratioThe yearly fee a mutual fund or ETF charges, stated as a percentage of your investment and taken out of the fund's assets instead of billed to you. A 0.03% ratio costs $3 a year per $10,000 invested; a 1% ratio costs $100. Lower is better.Full definition: 0.42%.
• State tax: interest is partially exempt from state income tax (the government-securities portion).
• Default sweep for Fidelity brokerage accounts; a core-position option for the Cash Management Account.

FZFXX (Fidelity Treasury Money Market Fund)

• Holds: US Treasury securities and repurchase agreements backed by them.
• 7-day yield as of October 15, 2026: 3.54%, slightly above SPAXX that day.
• State tax: only the Treasury-interest portion of the dividend is exempt from state income tax; the repurchase-agreement income is not verify×DON'T TRUST, VERIFYClaim: Interest on US Treasury securities is exempt from state and local income tax under federal law.Verify at: IRS Publication 550 ↗ · Fidelity 2025 US government income percentages ↗ Source 5 in the list below31 USC 3124 exempts US obligations from state and local taxation. The portion of an MMF that holds direct Treasuries is exempt; the repo portion is not.. Fidelity reported 61.52% of FZFXX's 2025 income as US government interest. California, Connecticut, and New York exempt none of it unless the fund holds at least 50% of its assets in US obligations at the end of every quarter, and FZFXX missed that test in 2024 and 2025.

FDLXX (Fidelity Treasury Only)

• Holds: only direct US Treasury obligations (no repurchase agreements).
• Highest state-tax exemption: 100% Treasury holdings, so 98.67% of its 2025 income was state-tax-exempt.
• 7-day yield as of October 15, 2026: 3.54% (the highest state-tax-exempt option for high-tax-state residents).
• Best for: very high state-tax residents who want maximum state-tax efficiency.

Worked-out after-state-tax math comparing FDLXX, SPAXX, and a top-of-market HYSA across no-state-tax, SC, CA, and NYC residents is on the FDLXX-inside-the-CMA section of the HYSA page.

VMFXX (Vanguard Federal Money Market) and SWVXX (Schwab Value Advantage)

Vanguard and Schwab equivalents of SPAXX. VMFXX is Vanguard's default cash sweep; SWVXX is bought manually at Schwab. Schwab also offers SNSXX (Schwab U.S. Treasury Money Fund), which holds Treasury securities directly; SNOXX holds Treasuries plus repurchase agreements backed by them, like FZFXX.

HYSA or money-market fund for the emergency fund?

Both work. A high-yield savings account is FDIC-insured to $250,000 and settles to your checking in a day. A government money-market fund like SPAXX or VMFXX sits inside your brokerage, yields roughly the same, and lets you deploy into investments instantly without a transfer. The deciding factor is usually your state tax rate.

Interest on Treasuries (T-bills, the Treasury slice of a money-market fund, I-bonds) is exempt from state and local income tax under 31 U.S.C. 3124. That exemption is worth roughly your state rate times the yield, and it flips the ranking once your state rate clears about 6%.

Section 3 · High-yield savings accounts (HYSA)

A HYSA is a bank savings account with a higher-than-average yield.

Differences from money market funds

• FDIC-insured up to $250,000 per depositor, per insured bank, for each account ownership category. Since the start of FDIC insurance on January 1, 1934, no depositor has lost a penny of insured funds as a result of a failure verify×DON'T TRUST, VERIFYClaim: FDIC deposit insurance covers $250,000 per depositor, per insured bank, for each account ownership category. Since the start of FDIC insurance on January 1, 1934, no depositor has lost a penny of insured funds as a result of a failure.Verify at: FDIC: What We Do (Deposit Insurance) ↗ Source 2 in the list belowBoth sentences appear on the FDIC's Deposit Insurance summary. The FDIC's explainer page dates the same record to the agency's founding in 1933.. Safer than MMFs in an extreme scenario.
• FDICFederal Deposit Insurance Corporation (FDIC)The US agency that insures bank deposits if a bank fails. The standard insurance amount is $250,000 per depositor, per insured bank, for each account ownership category. Since January 1, 1934, no depositor has lost a penny of insured funds as a result of a failure. Bank money market deposit accounts are covered; stocks, bonds, mutual funds (money market funds too) and crypto are not, even when bought at an insured bank. or NCUA insures HYSAs and CDs to $250,000 per depositor; at a bank, the FDIC limit applies per insured bank, for each account ownership category.
• Typically slightly lower yield than comparable MMFs.
• No state-tax exemption on interest.
• Yield moves up and down with the federal funds rate.

Top HYSA range as of mid-October 2026: approximately 3.9% to 4.27% APYAnnual Percentage Yield (APY)An annualized measure of deposit interest that includes the effect of compounding. It is not an inflation-adjusted or after-tax return.Full definition for top-tier accounts verify×DON'T TRUST, VERIFYClaim: Top-tier HYSA rates are approximately 3.9% to 4.27% APY as of October 13 to 16, 2026.Verify at: Bankrate HYSA tracker ↗ · NerdWallet HYSA list ↗ Source 6 in the list belowRates track the federal funds rate (target range 3.75% to 4.00% since the September 16, 2026 FOMC decision)..

Section 4 · T-bills and the CD ladder

T-bills (Treasury Bills)

Short-term US government debt with maturities from 4 weeks to 1 year. Why they are useful:

• Direct obligation of the US government.
• Interest fully exempt from state and local income tax.
• Higher yield than most bank savings accounts.
• Available directly at TreasuryDirect.gov or through any brokerage verify×DON'T TRUST, VERIFYClaim: Current T-bill yields can be looked up at TreasuryDirect or FRED.Verify at: TreasuryDirect.gov ↗ · FRED 1-month Treasury ↗ Source 7 in the list belowYields update each business day. The 4-week, 13-week, 26-week, and 52-week T-bills auction on a published schedule..

CD ladder

A CD ladder staggers Certificate of Deposit maturities so you have regular access to funds while earning higher yields than savings accounts. Example 5-rung ladder with $10,000:

• $2,000 in 3-month CD
• $2,000 in 6-month CD
• $2,000 in 9-month CD
• $2,000 in 12-month CD
• $2,000 in 15-month CD

As each matures, reinvest at the longest maturity or take cash if needed. Result: access to $2,000 every 3 months, with most of the money earning longer-duration yields. Online banks and credit unions typically offer higher CD rates than traditional banks. Build one in the CD ladder tool.

When do T-bills or CDs beat a savings account?

When you know the date. A savings account is best when you might need the money at any moment. Once the money has a deadline, a T-bill or CD maturing near that date usually pays a bit more and, for the T-bill, escapes state tax.

• T-bills in 4-, 13-, 26-, and 52-week maturities are direct US-government debt, fully state-tax-exempt, and buyable at TreasuryDirect or any brokerage. Best for money you can leave alone until a set date.
• The catch: a CD charges an early-withdrawal penalty, and a T-bill sold before maturity trades at market price. Neither is your emergency fund; both are for money with a known horizon.

Mechanics, auction timing, and when I-bonds beat T-bills are covered in depth on I-bonds and T-bills.

Section 5 · I-bonds

I-bonds are US savings bonds with inflation-adjustedInflation-adjustedAdjusted for rising prices. Some amounts move with inflation, like IRS tax brackets, TIPS principal, or I-bond rates. Others are restated in today's dollars so different years can be compared: by the BLS consumer price index, $30,000 in 1985 bought about what $93,000 buys in 2026. yields. The composite rate equals a fixed rate plus a semi-annual inflation adjustment.

Key features

• Purchase limit: $10,000 per person per year.
• Minimum hold: 12 months.
• Early-withdrawal penalty: 3 months interest if redeemed before 5 years.
• Interest deferred until redemption (federal-tax advantage).
• Interest exempt from state and local income tax.
• Cannot be sold on a secondary market. Must be redeemed at TreasuryDirect verify×DON'T TRUST, VERIFYClaim: I-bond purchase limit is $10,000 per person per year. Minimum 12-month hold. 3-month interest penalty if redeemed before 5 years.Verify at: TreasuryDirect I-bonds ↗ Source 8 in the list belowTreasury Direct is the only place to buy or redeem I-bonds..

When I-bonds make sense

• When the composite yield exceeds comparable T-bills or CDs.
• For 1-5 year money you definitely will not need for 12+ months.
• For inflation protection in the fixed-income portion of a portfolio.

When they do not: when you need the money within 12 months; when T-bill yields exceed I-bond composite yield; for amounts above $10,000/year.

I-bonds preserve purchasing power against the official basket; they do not grow it. For why even that basket understates your real cost of living, see the problem.

The takeaway is to hold only what safety and liquidity require, place it correctly, and stop treating the yield chase as a wealth strategy, not to abandon cash. See what your account earns over your horizon in the real return calculator, weigh whether the whole optimization game pays off on is chasing yield worth it, and read Bitcoin vs a savings account for where long-horizon savings might go instead.