The first reports filed under the SEC's amended Rule 605 show that market makers' price improvement stops at the $200,000 order mark: orders of $200,000 or more were filled at or near the quoted price, according to the new disclosures.

The finding comes from the initial reporting cycle under the amended rule, which for the first time requires execution-quality reports to include large orders. Regulators and buy-side desks can now see, order by order and size band by size band, where retail-style price improvement actually occurs — and where it does not.

What does the new Rule 605 reporting cover?

Rule 605 (the SEC rule requiring market centers to publish monthly standardized execution-quality statistics) was amended to close a long-standing blind spot. The old reports covered only small orders, the kind typical of retail flow, which meant institutional-size executions went unmeasured in the public dataset.

That gap is now closed in part. The first amended reports include large orders for the first time, giving compliance desks and best-execution committees a public benchmark for institutional fills rather than assertions from venue marketing.

The headline result is concrete. Orders of $200,000 or more were filled at or near the quoted price. In plain terms: the effective spread savings that wholesalers advertise on retail-size orders did not appear at institutional size.

Why the $200,000 threshold matters

For buy-side trading desks, the number functions as a marker. Below it, the new data shows fills that improve on the displayed quote — the internalized price improvement that market makers have built their retail franchises around. At and above $200,000, that improvement disappears, and executions cluster at or near the quoted price.

The implication for execution workflow is direct:

• Best-execution committees now have a public, standardized dataset covering institutional order sizes, not just retail clips.
• Sell-side desks routing parent orders can test, with measured data rather than vendor claims, whether splitting into child orders changes the price improvement received.
• Market makers' claims of spread savings can now be interrogated by size band, separating what is measured from what is asserted.

Mandated reporting, measured outcomes

Two distinctions are worth drawing. The amended reporting is mandated: market centers must file it, and the large-order coverage is now part of the rule set rather than a voluntary disclosure. The price-improvement finding, by contrast, is a measured outcome of the first reporting cycle — an empirical observation, not a regulatory conclusion about conduct.

That separation matters for how desks use the data. The rule does not require market makers to improve prices on large orders; it requires them to disclose what they actually do. The first cycle shows they do not, at least at or above the $200,000 threshold, where fills sat at or near the quote.

For technology teams, the new size-banded statistics add a dataset to ingestion and best-ex monitoring pipelines. For compliance, they add a benchmarkable reference point in monthly Rule 605 reviews.

Subsequent reporting cycles will show whether the pattern holds, and whether large-order execution quality shifts as market makers adapt to public scrutiny of institutional fills.