Prime money market funds (MMFs) are vulnerable to runs. This was dramatically illustrated in September 2008 and March 2020, when massive outflows from prime MMFs worsened stress in the short-term funding markets and eased only after taxpayer-supported interventions by the Treasury and the Federal Reserve. In this post, we describe how mechanisms like swing pricing that charge a price for liquidity can reduce the vulnerability of prime MMFs without triggering preemptive runs.
The money market industry is in the midst of significant change. With the implementation this month of new Securities and Exchange Commission rules designed to make money market funds (MMFs) more resilient to stress, institutional prime and tax-exempt funds must report more accurate prices reflecting the net asset value (NAV) of shares based on market prices for the funds’ asset holdings, rather than promising a fixed NAV of $1 per share. The rules also permit prime funds, which invest in a mixture of corporate debt, certificates of deposit, and repurchase agreements, to impose fees or set limits on investors who redeem shares when market conditions sharply deteriorate. (Funds investing in government securities, which are more stable, are not subject to the new rules.) These changes, driven by a run on MMFs at the height of the financial crisis, add to earlier risk-limiting rules on portfolio holdings.