German exchange operator Deutsche Boerse is calling for systematic internalizer to play by the same rules as exchanges when quoting prices, reported Bloomberg Markets.

Under MiFID II, systemic internalizers do not have to follow the same tick-size rules that everyone else does, said Alexandra Hachmeister, chief regulatory officer at the Frankfurt Strock Exchange, while being interviewed on Bloomberg television.

“There are some loopholes still in the document,” she noted.

Under the current rules, SI can offer customer quotes and do not need to disclose order size, which may give them an edge when competing against an exchange’s displayed order book.

If left unaddressed, experts expect equities trading occurring on non-displayed venues to grow by 100% to 200% before 2020.

However, the European Securities and Market Authority has responded to the rising criticism from the market earlier this month by proposing to bring the relevant portions regarding SIs in line with those regulations governing exchanges.