Liquidity Premium
The liquidity premium is the additional return that investors require to hold assets that are less liquid, that is, assets that cannot be bought or sold quickly without a significant price concession. It is one component of the term premium on longer-term bonds and a determinant of the yields on many financial instruments.
Sources of Liquidity Risk
Liquidity risk arises from the possibility that an asset cannot be sold when needed, or can be sold only at an unfavourable price. In normal markets, trading is easy and the premium is small. In stressed markets, liquidity can evaporate, and the premium rises sharply.
Liquidity risk has a market dimension, the cost of trading a given quantity, and a funding dimension, the risk that financing cannot be rolled over. Both can interact, particularly for institutions that rely on short-term funding to hold long-term assets, as the failure to roll over financing can force the sale of assets at depressed prices.
The Term Structure
In the expectations hypothesis of the term structure, long-term rates equal the average of expected future short-term rates, with no premium for maturity. In practice, long-term rates typically exceed this average, and the difference is the term premium, which includes compensation for interest rate risk and for the lower liquidity of long-term instruments.
The liquidity premium is closely related to the term premium but distinct, since term premia also reflect duration and inflation risk. Empirical decompositions attempt to separate these components, and the results suggest that the term premium varies over time and can be negative in some circumstances, as when investors seek the safety of long-term government bonds.
Evidence and Measurement
Evidence for liquidity premia comes from several sources. Assets with similar credit risk but different liquidity trade at different yields, with the less liquid trading at a discount. Episodes of market stress, in which the prices of illiquid assets fall sharply relative to comparable liquid assets, provide further evidence.
Measuring the premium is difficult because liquidity is not directly observable and because it varies with market conditions. Proxies include bid-ask spreads, trading volume, and measures of price impact, but no single measure captures all dimensions of liquidity.
Implications for Markets and Policy
Liquidity premia affect the cost of capital, the pricing of securities, and the allocation of portfolios. Investors demand compensation for holding illiquid assets, and issuers bear the cost through higher yields. During crises, spikes in liquidity premia can disrupt markets and impair the flow of credit, motivating central bank intervention to supply liquidity.
Understanding liquidity premia also informs the design of financial regulation, since requirements that affect dealer inventories and market-making can influence liquidity. The balance between measures that enhance resilience and those that impair market liquidity is a central concern of post-crisis regulation.
The Demand for Money and Liquid Assets
The liquidity premium is closely related to the demand for money and liquid assets. Because money and near-money assets provide liquidity services, investors accept lower yields on them than on less liquid assets. The size of the premium reflects the value of the liquidity services provided.
Theories of money demand analyse the trade-off between the liquidity of money and the return on less liquid assets. The premium adjusts to equate the supply and demand for liquidity, and changes in the premium reflect changes in liquidity preference or in the supply of liquid assets.
Liquidity and Asset Pricing
Liquidity is a priced characteristic of assets. Assets that are more liquid trade at higher prices and lower yields, and the premium for illiquidity is a component of expected returns. Empirical asset pricing models that include liquidity factors find that liquidity risk is priced, meaning that assets whose liquidity tends to deteriorate in bad times command higher expected returns.
The pricing of liquidity has implications for portfolio choice, since investors must weigh the return advantage of illiquid assets against their exposure to liquidity risk. Long-horizon investors with stable funding may be better placed to bear liquidity risk, and this reasoning underpins the allocation strategies of pension funds and endowments.
Liquidity in Crises
Liquidity premia spike during financial crises, when markets become illiquid and investors scramble for cash. The resulting price declines can be severe and can force further sales, creating a self-reinforcing cycle. The demand for liquid assets rises, and the prices of illiquid assets fall sharply.
Central banks respond by supplying liquidity, both through lending facilities and through asset purchases, aiming to reduce the premium and restore market functioning. The effectiveness of these measures depends on their scale, their design, and the sources of the liquidity shortage.
Regulatory Considerations
Post-crisis regulation has sought to enhance the resilience of institutions to liquidity shocks, including requirements on the composition of assets and the stability of funding. These measures reduce the vulnerability of individual institutions, but they can also affect market liquidity, since institutions subject to liquidity requirements may be less willing to hold and trade illiquid assets.
The balance between resilience and market liquidity is a central concern of regulatory design. Requirements that are too strict may impair the functioning of markets, while those that are too lax may leave institutions exposed. Calibration of the requirements must therefore consider both the stability of institutions and the liquidity of the markets in which they operate.