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M Mutual Funds, ETFs & Pooled Vehicles

Definition / Meaning of Money market fund

A money market fund is a type of mutual fund that invests in short-term, high-quality, low-risk debt securities. These funds are designed to offer investors a safe place to park cash while earning a modest return, typically higher than a standard savings account. Money market funds are regulated by the Securities and Exchange Commission (SEC) and are often used as a cash management tool by individuals and institutions. They aim to maintain a stable net asset value (NAV) of $1.00 per share, though this is not guaranteed.

How Money Market Funds Work

Money market funds pool money from many investors and use it to buy very short-term debt instruments. These include Treasury bills, commercial paper, certificates of deposit, and repurchase agreements. Because the investments mature in less than 13 months (and often much less), the fund’s value remains stable. Investors can buy or sell shares at any time, making money market funds highly liquid. The fund earns interest on its holdings, which is passed along to investors as dividends, typically credited monthly.

Key Features of Money Market Funds

  • Low Risk: Investments are in high-credit-quality securities, minimizing default risk.
  • Stable NAV: Most retail money market funds aim to keep a constant NAV of $1 per share.
  • High Liquidity: Shares can be redeemed on any business day, often with check-writing or debit card privileges.
  • Low Returns: Because risks are low, returns are generally lower than those of bond funds or stock funds.
  • Regulation: Strict SEC rules govern the maturity, credit quality, and diversification of holdings.

Types of Money Market Funds

There are several categories of money market funds, distinguished by the types of securities they hold:

  • Government Money Market Funds: Invest primarily in U.S. Treasury securities, agency bonds, and repurchase agreements backed by these. They are considered the safest type.
  • Prime Money Market Funds: Invest in short-term corporate debt, commercial paper, and bank obligations. They offer slightly higher yields than government funds but with marginally more risk.
  • Municipal Money Market Funds: Invest in short-term debt issued by states, cities, and other local governments. Their interest is often exempt from federal income tax, and sometimes state tax.
  • Treasury-Only Money Market Funds: A subset of government funds that invest only in direct U.S. Treasury obligations, offering the highest safety.

Who Should Use a Money Market Fund?

Money market funds are ideal for investors seeking a safe place to hold emergency savings, short-term cash reserves, or funds awaiting deployment into other investments. They are also commonly used in 401(k) and Traditional IRA accounts as a cash holding option. However, they are not suitable for long-term growth, as their returns typically only keep pace with inflation. For long-term goals, investors usually turn to higher-risk assets like stocks or bonds.

Pros and Cons

ProsCons
Low risk of lossLow returns, may not beat inflation
High liquidity and easy accessNot FDIC insured (unlike a savings account)
Stable $1 share price (most retail funds)Fees can eat into small returns
Diversified portfolio of short-term debtYields can fluctuate with interest rates

Comparing Money Market Funds and Money Market Accounts

It is important not to confuse a money market fund with a money market account. A money market account is a deposit account offered by banks and credit unions, insured by the FDIC or NCUA. A money market fund is an investment product offered by brokerage firms and fund companies, and it is not insured by the FDIC. Both offer competitive interest rates and limited check-writing, but the fund carries investment risk, however small.

Also Known As Money market mutual fund, Short-term bond fund, Cash reserve fund
Topics Mutual Funds, ETFs & Pooled Vehicles
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Last Updated May 2026

Related Terms

N No-load fund T Target-date fund C Closed-end fund S Share class B

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