In the second and third trades, there was price improvement because the sell orders were executed at bid prices higher than the quoted bid prices. Hence the effective spread was lower than the quoted spread. In the first trade, the trade size was larger than the bid size. The effective spread in this case was higher than that quoted due to the market impact of the large order.

Overall, the simple average effective spreads was lower than the average quoted spread, reflecting the price improvement in the last two trades. The weighted average effective spread was higher than the average quoted spread, reflecting the market impact of the first trade, which was relatively larger in volume than either of the last two trades