Money market funds are mutual funds that hold short-term, high-quality debt — primarily US Treasuries, government agency securities, and corporate commercial paper. They’re designed to maintain a stable $1.00 per share price and pay out interest as dividends. In 2026, government money market fund yields are competitive with high-yield savings accounts and serve as the default “cash” holding for many brokerage investors.
Key takeaway: Money market funds are a safe, liquid place to park cash at your brokerage while earning competitive yields. Government money market funds (holding only Treasuries and agency securities) are the safest type. They’re not FDIC-insured, but the risk of loss is very low.
Money Market Fund vs Money Market Account
| Feature | Money Market Fund | Money Market Account (MMA) |
|---|---|---|
| Where held | Brokerage / mutual fund company | Bank or credit union |
| FDIC/SIPC insured | Not FDIC-insured (SIPC-covered at some brokerages) | FDIC-insured up to $250,000 |
| Yield type | Variable (tied to short-term rates) | Variable (bank sets rate) |
| Minimum investment | Often $1 or $1,000 | Varies ($0–$2,500 typical) |
| Check writing | Some funds | Often yes |
| Risk | Very low | Very low |
| Liquidity | Same-day (T+1 settlement in some cases) | Immediate |
Practical note: The distinction matters mainly for account safety. For amounts under $250,000, the FDIC-insured MMA has a slight safety edge. For amounts over $250,000 (or spread across multiple accounts), government money market funds backed by US Treasuries are comparably safe.
Types of Money Market Funds
Government Money Market Funds (Safest)
Invest exclusively in US Treasury bills, Treasury notes, and US government agency securities (like FNMA or FHLB obligations).
- Examples: SPAXX (Fidelity), VMFXX (Vanguard), SWVXX (Schwab)
- Risk: Extremely low — backed by US government obligations
- State tax: Interest may be partly state-tax-exempt (check fund’s percentage in government securities each year)
- Typical yield: Slightly below prime money market funds
Retail/Prime Money Market Funds
Invest in a mix of Treasuries, government agency debt, and short-term corporate commercial paper from highly rated issuers.
- Higher yield than government-only funds (by 10–30 basis points, typically)
- Slightly more risk — exposure to corporate credit
- Available only to “retail investors” (individuals, not institutions) since SEC 2016 reforms
Municipal Money Market Funds (Tax-Exempt)
Invest in short-term municipal bonds. Interest is exempt from federal income tax.
- Best for: High-income investors in 32%+ federal brackets
- Lower nominal yield but higher after-tax yield for the right income level
- Less common and less liquid than government funds
Popular Money Market Funds in 2026
| Fund | Type | Ticker | Brokerage |
|---|---|---|---|
| Fidelity Government Money Market | Government | SPAXX | Fidelity |
| Fidelity Treasury Only Money Market | Government | FDLXX | Fidelity |
| Vanguard Federal Money Market | Government | VMFXX | Vanguard |
| Schwab Value Advantage Money Market | Government/Prime | SWVXX | Schwab |
| Schwab Government Money Market | Government | SNVXX | Schwab |
Yields: Check fund websites directly for current 7-day SEC yield, which reflects current market rates and changes weekly.
How Money Market Fund Yields Work
Money market fund yields are typically quoted as a 7-day SEC yield — the annualized net income earned over the past 7 days. This is the most standardized way to compare funds.
Example:
- 7-day SEC yield: 4.85%
- Monthly income on $50,000: $50,000 × (4.85% / 12) = ~$202
Yields fluctuate with short-term interest rates. When the Federal Reserve raises rates, money market yields rise. When the Fed cuts, yields fall.
Expense ratio matters: Compare funds on net 7-day yield (after expenses). A fund with a 5.00% gross yield and 0.40% expense ratio has a 4.60% net yield. A fund with a 4.90% gross yield and 0.10% expense ratio has a 4.80% net — meaningfully better.
Tax Treatment of Money Market Fund Income
| Income Type | Tax Treatment |
|---|---|
| Government fund dividends | Ordinary federal income; may be state-tax-exempt |
| Prime fund dividends | Ordinary income (federal + state) |
| Municipal fund dividends | Federal tax-exempt; may be state-exempt |
State tax exemption: If a government money market fund invests at least 50% of its assets in direct US government obligations (like T-bills), the dividends attributable to those obligations are typically exempt from state income tax. Many funds report this percentage annually — check the fund’s tax information page.
Fidelity SPAXX note: SPAXX holds some agency securities (FNMA, FHLMC) that may not qualify for state tax exemption in all states. FDLXX (Fidelity Treasury Only) holds exclusively Treasury bills and is fully exempt in most states. Check your state’s rules.
Using Money Market Funds as a Cash Management Tool
Common uses:
- Emergency fund — liquid, safe, higher yield than bank savings
- Investment dry powder — holding cash at a brokerage while waiting to invest
- Short-term savings goals — saving for a down payment, large purchase, or tax payment due in 1–2 years
- Overflow above FDIC limit — amounts above $250,000 that would exceed FDIC protection at a bank
Example portfolio role: You have $100,000 in emergency savings. Instead of leaving it in a 0.01% bank savings account:
- $10,000 in a checking account (immediate access)
- $90,000 in VMFXX at 4.85% → earning ~$4,365/year in interest
- Full withdrawal available next business day
Related Resources
- Interest Rates & Federal Reserve Guide — rate environment context
- HYSA vs Treasury Bills — comparing cash alternatives
- Treasury Bills Guide — T-bills vs money market funds
- Where to Put Short-Term Savings — cash placement strategy
The content on Wealthvieu is for informational purposes only and should not be considered financial, tax, or investment advice. Consult a qualified professional before making financial decisions. Full disclaimer · Editorial policy