After new regulation hit Europe's financial markets in January, traders are still divided as to its effectiveness six months on.
A chunky 70 per cent of traders think the second Markets in Financial Instruments Directive (Mifid II) has made trading more transparent, according to a survey by Swiss stock exchange Six.
But just a quarter think that dark pool trading, where trades can be completed on private venues without any of the usual reporting requirements, will shift to the transparent "lit" venues.
Driving trades to lit venues was one aim of the Mifid II regulation. Dark pools were originally created to allow large block trades to be completed away from public scrutiny, so as not to affect the market price before the deal was done, but they had been increasingly used as a means of keeping even tiny trades out of the public eye.
"This variance in responses highlights the reigning uncertainty among traders. Over time, market developments will provide more conclusive answers on the success of Mifid II," said Tony Shaw, London director of securities and exchanges at Six.
Mifid II has placed a cap on how much of any one stock can be traded in the dark over 12 months. If breached, dark trading in that stock will be suspended for six months.
But instead of driving activity to lit exchanges, traders seem to think liquidity will move to large-in-scale dark pools, where a waiver allows traders to complete hefty deals in the dark, systematic internalisers, which are investment firms and banks which can execute client orders on their own account, and periodic auctions.
Traders are also preoccupied by reporting, as 86 per cent of respondents cited transaction reporting and best execution reporting as causing the most concern under Mifid II.
An overwhelming 87 per cent believe that the increased volatility which emerged in markets in February is a trend that will continue. Interestingly, three quarters of traders stated that exchange-traded funds, which track an index, have contributed to this rise in volatility.