This paper assesses the determinants of market impact costs of institutional equity trades, using unique data from the world's second largest pension fund. We allow the impact of trade characteristics and market conditions on trading costs to depend on the level of trading costs itself and...

Often, a relatively small group of trades causes the major part of the trading costs on an investment portfolio. For the equity trades studied in this paper, executed by the world's second largest pension fund, we find that only 10% of the trades determines 75% of total market impact costs....

This paper is the first to analyze market impact and execution costs of equity trading by a pension fund. We find that, on average, these costs are nonnegligible. Average market impact costs equal 20 basis points for buys and 30 basis points for sells; average execution costs equal 27 basis...