We analyze the ability of various market mechanisms to provide liquidity for large equity trades. Using data on 21,077 block transactions in Dow Jones stocks, we find that the "downstairs" NYSE floor market is a significant source of liquidity. Although negotiation in the informal "upstairs" market provides better execution than the downstairs market for large trades, these differences are economically small. We find, however, that upstairs markets are used by traders who can credibly signal that their trades are liquidity motivated. Thus, upstairs markets allow trades that may not otherwise occur.

The author derives the limiting properties of the two-stage least squares estimator of an equation in a dynamic simultaneous model when variables are nonstationary and cointegrated. The implication on hypothesis testing is also discussed. It is shown that, in a structural equation approach, what one needs to worry about are the classical issues of identification and estimation, not nonstationarity and cointegration. Conventional formulae for computing the asymptotic covariance of the two-stage least squares estimator and the Wald-type test statistics remain good approximations despite the fact that variables may be integrated. Copyright 1997 by The Review of Economic Studies Limited.

The author demonstrates that despite variables that are integrated, the fundamental issues on structural equation modeling raised by the Cowles Commission remain valid and standard estimation and testing procedures can still be applied. A basic framework linking the multiple time series model and the dynamic simultaneous equation model is provided and implications under the long-run cointegrating relations are discussed. Conditions for identifying both the short-run dynamics and long-run equilibrium conditions are given. Limiting properties of the least squares and simultaneous equation estimators under cointegration are derived. Implications for hypothesis testing are also discussed.

We analyze the ability of various market mechanisms to provide liquidity for large equity trades. Using data on 21,077 block transactions in Dow Jones stocks, we find that the “downstairs” NYSE floor market is a significant source of liquidity. Although negotiation in the informal “upstairs” market provides better execution than the downstairs market for large trades, these differences are economically small. We find, however, that upstairs markets are used by traders who can credibly signal that their trades are liquidity motivated. Thus, upstairs markets allow trades that may not otherwise occur.