What Are Money Market Funds?

Every time you go to the grocery store, you’re bombarded with thousands of options lining the shelves—some that are really good for you and some that are straight up junk. Investing in the stock market is the same way. There are good investments and bad investments. And one type of investment you might find on the shelves is something called a money market fund.

Money market funds (sometimes called money market mutual funds) have grown more popular over the years, with around $3.6 trillion being managed across hundreds of different money market funds out there.¹ That’s a lot of money!

Money market funds are seen in the investing world as a type of low-risk, low-reward alternative to investing in stocks—especially for investors just looking for a place to park their money or protect their retirement savings as they get closer to retirement. But should they have a place in your financial plan, or are you better off investing your heard-earned cash elsewhere? Let’s take a look. 

What Are Money Market Funds?

A money market fund is just a type of mutual fund invested in short-term debt securities. We like to describe mutual funds like this: If a group of people were standing around an empty bowl and each person threw in a $100 bill, they would be mutually funding the bowl. Makes sense, right?

And short-term debt securities is just a fancy way to say money loaned to governments, corporations and banks that’s due back to investors in less than a year, plus interest. In this case, you are the lender, and they are the borrower. (Just like if you own certificates of deposit or bonds.)

How Money Market Funds Got Popular

Money market funds haven’t been around all that long. The first fund was cooked up by a couple of guys in the early 1970s as a way to offer investors something that would keep their cash safe and also earn them a little interest. Even though losses are rare, they can still happen. We’ll share how it happened not all that long ago later on.

Money Market Funds vs. Money Market Accounts: What’s the Difference?

Now, before we dig deeper into money market funds, don’t miss this: Money market funds are not the same as money market accounts. 

Money market accounts are basically savings accounts offered by a bank or credit union, while money market funds are investments. Big difference!

How Do Money Market Funds Work?

Like most other mutual funds, investors pool their money together to invest in something. (Remember the empty bowl we were just telling you about.) Except in this case, these investors are not investing in stocks. Instead, they’re investing in debt instruments sold by governments, companies and sometimes banks that allow those entities to borrow money for a short period of time. And no, a debt instrument is not like a guitar or set of drums. It’s just another way of describing a tool that an entity—like a government or company—can use to raise money.   

Money market funds are in the family of fixed-income investments, which means they’re designed to give investors a steady stream of income on a regular basis in the form of interest payments.

You can buy money market funds from brokerage firms or directly through a bank that sells them. Depending on the type of fund, you might have to put down some type of minimum deposit—anywhere from a few hundred dollars to $5,000—just to get started buying money market funds. But there are some brokerage firms that will let you get started with no minimum deposit at all.

Here are some of the main characteristics of money market funds to keep in mind.

Money market funds are relatively low-risk investments.

Money market funds are considered “safe” investments because these loans come due within a very short period of time—usually 90 days or less. On the risk scale, they’re less risky than investing in stocks but riskier than parking your money in a savings account. 

Money market funds are highly liquid.

If a company, bank or government has enough assets to meet their financial commitments, then they’re liquid—or they’re good for it. When it comes to money market funds, that means the investments inside of a money market fund can be quickly turned into easily accessible cash. 

Money market funds have slightly better returns than savings accounts.

Here’s our biggest issue with money market funds: their performance! You can probably expect around 2–3% returns from a money market fund. And while that might be better than the returns you’ll find with a savings account, it’s still nothing to write home about. Plus, that’s before the fees and expenses, which cut into your returns even more. And that level of return is definitely not going to be enough to help you save for retirement (more on that in a minute).

What Are Different Types of Money Market Funds?

There are a bunch of different types of money market funds out there, but we can pretty much boil them down to three main categories: prime funds, government and treasury funds, and tax-exempt (or municipal) funds. Let’s break each of those down real fast:

Prime funds

Sometimes referred to as commercial paper, prime funds are money market funds that are usually invested in corporate debt. Translation? Investors lend money to the companies in the fund, and in return, the companies promise to pay you back quickly, with a little interest for your trouble.

Government and treasury funds

Government and treasury funds are usually invested in things like treasury bonds or other government-backed debt securities used to raise money for government spending. Don’t you worry—they promise to pay you back too.  

Tax-exempt funds

Often called municipal funds, tax-exempt funds are unique from prime and government or treasury bonds because the money you earn is free from U.S. federal income tax (and in some cases, from state taxes as well). These funds are usually invested in municipal bonds that raise money for local governments.

Are Money Market Funds Worth Investing In?

The short answer: absolutely not! Here’s why:

Market chaos, inflation, your future—work with a pro to navigate this stuff.

First off, they’re terrible for long-term investing. Remember those wimpy 2–3% returns? That’s nowhere near high enough to help you reach your retirement goals! The cost of things is always rising—usually somewhere between 2–3% every year. That’s called inflation, and you need to invest at a rate that’s higher than inflation.

Most investors who buy money market funds do so because they want to get a slightly better return on their investment than a high-yield savings account . . . but “safe” doesn’t mean money market funds are a sure thing.

During the 2008 financial crisis, one of the most popular money market funds collapsed and investors ended up losing money.² And when the COVID-19 global pandemic hit in 2020, the total value of money market funds that buy corporate debt dropped by $120 billion—that means 15% of all the money tied up in money market funds was wiped out.³

So, if you’re just looking for a place to park some money or you’re saving for a short-term financial goal—think less than five years—you’re better off putting that money in a money market account than you are in a money market fund. Sure, you’re not getting a great rate of return, but you’re also avoiding the risk of dealing with that kind of market volatility in the short term. 

There’s a Better Way to Invest

When it comes to saving for retirement, we recommend investing 15% of your gross income in good growth stock mutual funds inside tax-advantaged retirement accounts like a 401(k) or Roth IRA.

But listen, you should never invest in something you don’t understand. That’s why we always think it’s a good idea to work with an investment professional who can sit down with you and teach you all the ins and outs of investing. That way, you can be confident in the decisions you’re making with your money!

Don’t have an investment pro? Our SmartVestor program can help you find a qualified investment pro that can help you get started.

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