Steven Maijoor, chair of the European Securities and Markets Authority (ESMA), said MiFID II rules launched in January are indeed living up to expectations of pushing more trading onto exchanges, but more work may be required.

In remarks before the World Federation of Exchanges annual meeting in Athens, Maijoor said less trading volume is flowing to dark pools and onto exchanges and so-called systematic internalisers (SIs), used by banks and algorithmic trading firms to fill customer orders. The use of ongoing periodic auctions for contracts, however, is coming under greater scrutiny, Maijoor said. These millisecond auctions may not being adhering to the rules set out in MiFID II.

“We have currently an assessment that some of these periodic auction trading systems may be there to circumvent the double volume cap regime,” Maijoor said. “We’re looking into these systems more carefully and expect in the coming months to start a call for evidence. We then will see if any further measures are needed.”

This is an important regulatory step for exchanges, which stand to benefit from more volume flow onto lit markets. Maijoor emphasized several times that a key goal of MiFID II was transparency.

“There have been concerns from trading venues about the level trading field between themselves and the SIs,” he said, adding that there has been a growing volume shift toward SIs.

He added that the regulator has proposed changes to the tick size requirement for SIs, to put them on par with exchanges.

Jan Boomaars, CEO of Optiver, stood in support of lit, traded markets in an adjoining panel.

“We believe in the lit model,” he said. “Everyone has an even chance.”

It is unclear when ESMA or the European Commission will make a move, but pushing equal trading rules for exchanges and SIs is likely to benefit listed exchange structures.