Personal Finance

What Is a Money Market Fund?

A money market fund is a mutual fund that invests in short-term, high-quality debt, such as Treasury bills and commercial paper, aiming to preserve value while paying interest. Many are designed to keep a stable value of 1 per share. It is an investment, not a bank deposit, and is not FDIC-insured.

Fund vs. Account

A money market account is a bank deposit that is FDIC-insured; a money market fund is held at a brokerage or fund company.

Yield

Yields change with short-term interest rates and are often expressed as a seven-day yield.

🧮 Calculate It Yourself

Put Money Market Fund into practice with these free calculators — no sign-up, nothing stored.

📈 APY Calculator Convert an interest rate to APY for any compounding frequency, and see a year’s interest. Calculate → 🎯 Savings Goal Calculator Find out how much to save each month to hit your target. Calculate →

🔗 Related Terms

Money Market Account Treasury Bill (T-Bill) FDIC Insurance Liquidity

More Personal Finance Terms

📖 Browse all glossary terms or explore all free calculators.

Last updated: September 29, 2026. This definition is for general educational purposes only. It is not financial, investment, tax, legal, or medical advice, and it does not recommend any product or course of action. For decisions about your own situation, consult a qualified professional.