The SEC moved to eliminate the equities trade-through rule, a core market-structure safeguard that bars venues from executing orders at prices worse than the national best bid or offer.
The proposal targets a rule in force since 2005 that applies to exchanges, alternative trading systems and wholesalers including Citadel Securities and Virtu Financial.
By removing that requirement, the agency would unwind a protection designed to help ensure individual investors receive the best available displayed price on stock trades.