Abstract This paper establishes liquidity linkage between stock and Treasury bond markets. There is a lead-lag relationship between illiquidity of the two markets and bidirectional Granger causality. The effect of stock illiquidity on bond illiquidity is consistent with flight-to-quality or flight-to-liquidity episodes. Monetary policy impacts illiquidity. The evidence indicates that bond illiquidity acts as a channel through which monetary policy shocks are transferred into the stock market. These effects are observed across illiquidity of bonds of different maturities and are especially pronounced for illiquidity of short-term maturities. The paper provides evidence of illiquidity integration between stock and bond markets.

Given the key role of liquidity in finance research, identifying high quality proxies based on daily (as opposed to intraday) data would permit liquidity to be studied over relatively long timeframes and across many countries. Using new measures and widely employed measures in the literature, we run horseraces of annual and monthly estimates of each measure against liquidity benchmarks. Our benchmarks are effective spread, realized spread, and price impact based on both Trade and Quote (TAQ) and Rule 605 data. We find that the new effective/realized spread measures win the majority of horseraces, while the Amihud [2002. Illiquidity and stock returns: cross-section and time-series effects. Journal of Financial Markets 5, 31–56] measure does well measuring price impact.