The upstairs market for large-block transactions: analysis and measurement of price effects

This article develops a model of the upstairs market where ordersize, beliefs and prices are determined endogenously. We testthe model's predictions using unique data for 5,625 equity tradesduring the period 1985 to 1992 that are known to be upstairstransactions and are identified as either buyer or seller initiated.We find that price movements prior to the trade date are significantlypositively related to trade size, consistent with informationleakage as the block is 'shopped' upstairs. Further, the temporaryprice impact or liquidity effect is a concave function of ordersize, which may result from upstairs intermediation.