Flight to Liquidity
Flight to liquidity is the tendency of investors during periods of market stress to shift holdings from less-liquid assets into highly liquid instruments — such as on-the-run US Treasuries or money market funds — even when the less-liquid assets carry equivalent credit quality, reflecting the premium investors place on the ability to transact immediately at low cost.
Flight to liquidity is closely related to but conceptually distinct from flight to quality. Flight to quality is about credit risk and default risk — moving from higher-credit-risk to lower-credit-risk assets. Flight to liquidity is about transaction ease — moving from harder-to-sell assets to easier-to-sell assets, regardless of credit quality. Both phenomena often occur simultaneously during crises, but they can be disaggregated.
A classic example: during the 2008 crisis, the spread between on-the-run US Treasury notes (the most recently issued and therefore most actively traded) and off-the-run Treasuries of the same maturity and credit quality widened significantly. Both instruments are obligations of the US government with identical default risk. The spread reflected a liquidity premium — investors were willing to accept a lower yield (higher price) for the on-the-run note because it could be sold quickly in large size with minimal market impact.
The same dynamic appears in corporate bond markets, mortgage-backed securities, municipal bonds, and equity markets. Small-cap stocks and thinly traded ETFs experience disproportionate selling pressure during crises because investors who need liquidity sell what they can, not what they want to. This forced selling of liquid assets can depress them below fundamental value and create opportunities for long-term investors who are not constrained sellers.
Money market funds are a primary destination for flight-to-liquidity flows. During the 2008 crisis, the breaking of the buck by the Reserve Primary Fund — caused by its holdings of Lehman Brothers commercial paper — triggered a broader panic-driven flight out of prime money market funds into government money market funds, which hold only Treasuries and agency securities. The US government ultimately provided a temporary guarantee to prevent further runs.
For portfolio managers, understanding the flight-to-liquidity dynamic helps explain why liquidity risk management is distinct from credit risk management. Holding a reserve of highly liquid assets — sometimes called a liquidity buffer — provides the capacity to meet redemptions and margin calls during crises without being forced to sell core portfolio holdings at distressed prices.