Definition
Best execution is the regulatory and contractual obligation on a firm executing orders to take sufficient steps to achieve the most favorable outcome for the client, taking into account price, costs, speed, likelihood of execution, settlement, order size, and other relevant factors. In traditional equity markets, best execution is codified under MiFID II in Europe and FINRA Rule 5310 in the United States. In digital assets, MiCA Article 76 imposes best-execution obligations on EU crypto-asset service providers, and the SEC's enforcement posture applies existing best-execution expectations to digital assets classified as securities.
Example
A broker receives a client order to buy 10 BTC. Under best execution, the broker must demonstrate that the chosen execution venue, timing, and algorithm resulted in a price as favorable as reasonably available given prevailing market conditions, and maintain TCA documentation to support the claim under audit.
How Liquid Mercury Handles This
Mercury Pro produces on-demand best-execution reports with venues considered, venue fills, price and time priority, latency attribution, and the decision trail, all sized for SEC Rule 17a-4 and MiCA Title V retention.