Has Any Money Market Fund Ever Broken the Buck? Historic Cases & Lessons

Let’s be honest — when people put money into a money market fund, they expect it to be as safe as cash. I’ve heard it called “the next best thing to a savings account.” But the term “break the buck” sends chills down any investor’s spine. It’s the moment when a fund’s net asset value (NAV) drops below $1 per share. Yes, it has happened. And the stories behind those events are worth knowing — not just for trivia, but for your own financial safety.

I’ve spent years tracking fund performance and talking to advisors, and I can tell you: the two major cases are both fascinating and terrifying. Let’s dive in.

What Does “Break the Buck” Actually Mean?

Money market funds aim to maintain a stable NAV of $1.00. When a fund “breaks the buck,” its NAV falls below that magic number — say, to $0.97. That means if you invested $1,000, you might get back only $970. For a product marketed as “cash-like,” that’s a big deal.

Most money market funds invest in short-term, high-quality debt (Treasuries, CDs, commercial paper). But when a major holding defaults or loses value, the math can turn ugly. The fund manager then has to write down the asset, and the NAV drops. Historically, only a tiny number of funds have ever broken the buck, but the consequences rippled across the entire financial industry.

The 1994 Case: Community Bankers U.S. Government Money Market Fund

I remember reading about this one years ago — it’s often overlooked because it was small. But it set a precedent.

What happened: This fund, run by Community Bankers, invested heavily in adjustable-rate securities tied to the U.S. government. In 1994, interest rates rose sharply, and the fund’s derivatives structure collapsed. The NAV fell to about $0.94. The fund liquidated, and investors lost roughly 6% of their money.

Why it matters: This was the first time a money market fund truly broke the buck. The SEC took note, but no major rule changes came immediately. Many in the industry thought it was a one-off anomaly.

Key takeaways from 1994:

• The fund was not a typical prime fund; it invested in complex derivatives.
• Losses were relatively small — about $100 million total.
• The event proved that “government” in the name doesn’t guarantee safety if the fund uses leverage or derivatives.

The 2008 Case: Reserve Primary Fund – The One Everyone Remembers

This is the big one. In September 2008, the Reserve Primary Fund (the oldest money market fund, founded in 1970) announced that its NAV had fallen to $0.97 after writing off $785 million in debt from Lehman Brothers. Lehman had just filed for bankruptcy, and the fund held a massive chunk of its commercial paper.

The panic was instant. Investors rushed to redeem — over the next few days, the fund faced redemptions of about $40 billion. The fund had to suspend withdrawals and eventually liquidate. In the end, investors got back about 99 cents on the dollar, but the psychological damage was done. It triggered a run on money market funds across the country, forcing the Treasury to step in with a temporary guarantee program.

Why it matters: This event changed the money market fund industry forever. It also showed that even a highly regarded, 38-year-old fund could break the buck if it took concentrated credit risk.

Comparison of the Two Breaches

Why Did These Funds Fail? The Real Reasons

After reading countless post-mortems, I see two common threads:

1. Concentration risk. The funds put too many eggs in one basket. Reserve Primary had 1.2% of assets in Lehman commercial paper — that’s a huge single-name exposure for a money market fund. Community Bankers leveraged derivatives tied to a narrow set of securities.
2. Illiquidity. When panic hits, money market funds can’t instantly sell their holdings at fair value. The NAV calculation relies on mark-to-market, and distressed sales force the NAV down. Both funds faced a liquidity crunch.

I’ve also spoken to fund managers who admit that internal risk models underestimated tail risks. They didn’t think a AAA-rated commercial paper issuer like Lehman could go bankrupt. Well, it did.

Regulatory Changes After the Breaches

After 2008, the SEC completely rewrote the rules for money market funds. Here’s what changed:

• Requirement to float the NAV for institutional prime and municipal funds (2014). Retail funds and government funds can still keep a stable $1.00 NAV.
• Liquidity fees and redemption gates — funds can impose fees or temporarily halt withdrawals if weekly liquid assets fall below a threshold.
• Stress testing — funds must test their portfolios against hypothetical interest rate and credit scenarios.
• Diversification rules — tighter limits on single-issuer exposure (no more than 0.5% for second-tier securities, 5% for first-tier).

These reforms made breaking the buck much less likely, but not impossible. I’ve seen some critics argue that the reforms pushed risk into the shadows — like the rise of “stable value” funds or private liquidity funds.

How to Protect Yourself as an Investor

If you’re holding money market funds, here’s my personal checklist:

• Stick to government money market funds (Treasury or agency). They have the lowest risk. In the 2008 crisis, government funds didn’t break the buck.
• Check the fund’s holdings. Look for heavy exposure to corporate commercial paper or asset-backed securities. If the fund has more than 10% in “unrated” or “second-tier” paper, I’d be cautious.
• Know the liquidity gates. Some funds now have the ability to block withdrawals. In a panic, you might not get your money immediately. If you need instant access, consider a high-yield savings account instead.
• Diversify across funds. Don’t put your entire emergency fund into one money market fund. Spread it across two or three different providers.
• Monitor for credit events. I personally set up Google Alerts for large commercial paper issuers. When something looks shaky, I move to government funds.

Frequently Asked Questions