2008 Money Market Fund Runs
2008 Money Market Fund Runs
In September 2008, the Reserve Primary Fund, a $62 billion money-market fund holding commercial paper and short-term bonds, fell below $1 per share as Lehman Brothers' bankruptcy forced it to write down its holdings, triggering a modern bank run as investors simultaneously withdrew from money-market funds and threatening to freeze the entire short-term lending market.
Key takeaways
- Money-market funds (MMMFs) invest in 90-day or shorter debt and are marketed as cash equivalents with minimal risk and stable $1 per-share value.
- The Reserve Primary Fund's exposure to Lehman Brothers commercial paper caused it to fall to $0.97 per share, "breaking the buck" and shattering investor confidence.
- As investors pulled cash from money-market funds, the funds were forced to sell illiquid short-term bonds, driving prices lower and spreading losses.
- The Fed established the Asset-Backed Commercial Paper Money Market Mutual Fund Liquidity Facility (AMLF) to provide emergency liquidity and guarantee money-market fund accounts.
- The 2008 money-market run exposed that cash is not a safe haven when the banking system itself is at risk of failure.
The Money-Market Fund Illusion
Money-market funds were designed to be the safest investment available, just slightly riskier than a bank deposit but with competitive yields. A MMFUND invested in very short-term instruments: US Treasury bills (90 days or less), commercial paper (short-term corporate borrowing), and municipal notes.
The appeal to investors was obvious. In normal times, a money-market fund yielded 4–5% while a bank savings account yielded 1–2%. There was no credit risk, the fund promised, because everything matured within 90 days. And because the fund held a portfolio of diversified short-term instruments, one issuer's failure could not hurt you.
By 2008, money-market funds held approximately $3.8 trillion in assets. Corporations used them to manage their cash. Pension funds held them as a money substitute. Retail investors, fleeing stocks, moved into money-market funds expecting stability.
But the fund industry had grown complacent. To compete on yields, money-market funds had lengthened the average maturity of their holdings (from 30 days to 45 days or more) and diversified into riskier assets: asset-backed securities (ABS) tied to mortgages, commercial paper from financial institutions, and leveraged loans.
The Reserve Primary Fund, one of the largest and most prestigious, had taken the trend further. It held significant exposure to Lehman Brothers commercial paper (short-term borrowing) and structured credit instruments. The fund's marketing emphasized safety and stability; its prospectus promised that the fund's average maturity was conservative.
The Lehman Shock
When Lehman Brothers filed for bankruptcy on September 15, 2008, the shock to the money-market system was immediate. Lehman had billions in commercial paper outstanding—essentially IOUs that were now worth cents on the dollar. The Reserve Primary Fund held approximately $600 million in Lehman commercial paper and related instruments.
The fund announced that it would not be able to honor all redemption requests at $1 per share. On September 16, 2008, the Reserve Primary Fund announced it would pay shareholders $0.97 per share on their redemptions. It had broken the buck.
The breaking of the buck was not merely a financial loss; it was a breach of the implied contract between the fund and its investors. Investors had believed their money in a money-market fund was safe. The loss of just 3 cents per dollar seemed small until you scaled it across a $62 billion fund and realized that the safety you had been assured was an illusion.
The Flight from Liquidity
The Reserve Primary Fund's problems were not unique. Other money-market funds held Lehman paper. Some held mortgage-backed securities that were now failing. As the scope of losses became clear, investors panicked.
The mechanism was like a traditional bank run: investors, fearing losses, rushed to redeem their shares at $1. Money-market funds, facing redemption requests, were forced to liquidate their portfolios to raise cash. But if you have to sell commercial paper or asset-backed securities in a market where prices are collapsing, you compound the losses.
The Lehman bankruptcy had frozen the commercial paper market. Companies that depended on rolling over commercial paper to fund operations faced a sudden refinancing crisis. Money-market funds, seeing yields rise (as credit spreads blew out), began refusing to buy new commercial paper at almost any yield.
The result was a liquidity squeeze that threatened the entire financial system. Companies that might be solvent but could not fund their payroll became at risk of failure. Banks that relied on money-market funding faced withdrawals and funding pressures.
By late September 2008, total outflows from money-market funds reached an estimated $300 billion per week. The system was on the verge of collapse: if investors continued to withdraw, and money-market funds had to sell at fire-sale prices, the cascade of losses would have destroyed the entire commercial paper market and frozen short-term lending for weeks or months.
The Federal Reserve's Intervention
The Federal Reserve, recognizing the systemic risk, moved decisively. The Fed created the Asset-Backed Commercial Paper Money Market Mutual Fund Liquidity Facility (AMLF) and the Commercial Paper Funding Facility (CPFF). The AMLF provided emergency liquidity to banks so they could lend to money-market funds. The CPFF allowed the Fed to lend directly to the commercial paper market, enabling corporations and financial institutions to issue new commercial paper.
But these mechanisms took time to operate. The immediate problem was panic. To halt the run, the US Treasury, coordinating with the Fed, announced a temporary guarantee: the government would insure money-market fund holdings up to $1 per share, similar to the FDIC insurance on bank deposits.
This guarantee, announced on September 19, 2008, was extraordinary. It essentially converted money-market funds into government-backed entities. It also signaled to investors that the government would not allow the money-market system to collapse.
The guarantee worked. Redemption requests slowed. Investors, reassured by government backing, stopped rushing to withdraw. The commercial paper market, with the Fed's CPFF behind it, stabilized. By October 2008, the worst of the money-market crisis had passed, though the damage to confidence persisted for months.
Structural Failures
The 2008 money-market crisis exposed deep structural flaws. First, the rating of money-market funds as safe, and the investor perception of them as cash equivalents, was not supported by actual holdings. A money-market fund holding mortgage-backed securities or long-dated asset-backed securities (not rolling over within 30 days) is not equivalent to cash or Treasury bills.
Second, the redemption feature—the ability to withdraw at $1 per share on any business day—created a liquidity mismatch. If a fund is required to pay out $1 per share on demand but holds illiquid securities, a run is catastrophic. This is the classic liquidity-transformation problem that banks face; the money-market fund industry had not fully grasped this risk.
Third, the interconnectedness of money-market funds with the banking system meant that a money-market crisis became a banking crisis. Banks relied on money-market funding; when money-market funds withdrew that funding, banks faced funding stress. The reverse was also true: the Reserve Primary Fund's losses came from exposure to Lehman, a major bank.
The Regulatory Response
The Securities and Exchange Commission (SEC) eventually tightened rules for money-market funds. Funds were required to hold a higher fraction of ultra-liquid assets (Treasury bills, not structured securities). Maturity restrictions were tightened. Gates (the ability to suspend redemptions) and fees (the ability to charge a premium to redeem in a crisis) were allowed, though rarely used.
The Fed's emergency lending facilities, created in 2008, became permanent fixtures. The CPFF was re-established in 2020 during the pandemic shock, and it worked similarly effectively.
But the deeper lesson—that money-market funds are not actually cash and can fail in a generalized financial crisis—never fully took hold in the public consciousness. To this day, many retail investors treat money-market funds as equivalent to bank deposits, not understanding that they can lose principal.
The Investor Lesson
For bond and cash-holding investors, the 2008 money-market crisis illustrated that "safe" is contextual. A money-market fund is safe in normal times, when credit spreads are tight and issuers are meeting their obligations. But in a financial crisis, when confidence breaks down, nothing is safe except US Treasuries and FDIC-insured bank accounts.
The crisis also illustrated the importance of liquidity in a crisis. A bond you cannot sell, or can only sell at a huge loss, is a liability, not an asset. Money-market funds that held illiquid asset-backed securities or off-the-run commercial paper discovered this harshly.
For those who had followed a simple rule—keep 3 to 6 months of expenses in a money-market fund or MMFUND—the crisis created doubt. Some retreated to FDIC-insured savings accounts, accepting lower yields for genuine safety. Others, notably institutional investors, moved to Treasury bills and Treasury direct purchases, cutting out the intermediary.
Process
Next
Even as the money-market crisis was unfolding, another major bond market shock was arriving: the flight to quality, where investors dumped credit-risky bonds and Treasury yields collapsed, setting the stage for the next phase of the 2008 crisis.