ESMA has published an economic report on order duplication and liquidity measurement in EU equity markets. The report forms the second part of ESMA's high-frequency trading (HFT) research. ESMA found that overall multi-venue trading has increased the liquidity in EU equity markets, but that duplicated orders and immediate cancellation lead to the overestimation of available liquidity in fragmented markets, which means that a certain percentage of the liquidity visible in order books is ultimately not available to the markets. Other points of interest include: (i) order duplication is more recurrent for HFT; and (ii) the proportion of immediate cancellations after the trade's execution is higher than the average for HFT traders.