NYSE-Affiliated Exchanges Adopt Best-Execution Rules

Four NYSE exchanges adopted rules requiring their members to seek the most favorable price for customer orders, thereby harmonizing their best-execution standards with those of other markets. 

The new rules were filed for immediate effectiveness and published in the Federal Register under NYSE Arca, NYSE National, NYSE American, and NYSE Texas.

New Rule 11.5310 ("Best Execution") requires a member to use "reasonable diligence" to find the best market for a security and to buy or sell there so that the price to the customer is as favorable as possible under prevailing conditions. It lists five factors for measuring that diligence: the character of the market, including price, volatility, and liquidity; the size and type of the transaction; the number of markets checked; the accessibility of the quotation; and the terms of the order. The rule also bars a member from placing a third party between itself and the best market in a way inconsistent with that duty.

The exchanges modeled the rule on Nasdaq PHLX Rule General 9, Section 11 and on NYSE Rule 5310, which the New York Stock Exchange adopted in January 2026. Those rules trace to a NASD rule from the 1990s that FINRA adopted as Rule 5310 in 2011. The exchanges said adopting consistent standards would lower the burden on firms that operate across multiple venues and ease compliance.

Accompanying guidance defined "market" broadly to cover exchange and off-exchange venues, clarified when the duty applies to orders routed from another broker-dealer, and provided that a member need not seek best execution beyond a customer's specific routing instruction.