Over a two-year period until September 2014, the market-maker removed hundreds of thousands of large OTC orders from its automated trading processes, according to Finra. That rendered the orders “inactive” and so they had to be handled manually by human traders.
Citadel Securities then “traded for its own account on the same side of the market at prices that would have satisfied the orders,” without immediately filling the inactive orders at the same or better prices as required by Finra rules, the regulator said….
Nearly half of the 467 limit orders reviewed by the regulator in the six years until September 2018 were found to violate Finra’s requirements to display orders. The bulk of the violations were for failing to execute trades against existing quotations in a timely manner, Finra said.