The expanded US Rule 605 execution-quality regime has applied since 1 August, bringing more broker-dealers and order types into public monthly reporting. The next phase begins on 1 November, when reports must start measuring price improvement against the best available displayed price, including disseminated odd-lot prices where they beat the round-lot national best quote.[1][3]
Rule 605 reports are not a ranking of brokers by one number. They divide orders by security, order type and size, then report execution speed, price improvement, spreads, fill outcomes and other statistics. The 2024 amendments were designed to capture modern retail order flow that the older framework treated incompletely.[2][1]
More firms and more order types enter the reports
Major changes effective from 1 August 2026
| Change | Earlier gap | New evidence |
|---|---|---|
| More reporting entities | The rule centred on market centres and did not capture every large customer-facing broker or single-dealer platform. | Specified broker-dealers with larger customer bases and single-dealer platforms now publish reports.Source 2Source 1 |
| More order types | Outside-hours, stop and some short-sale orders were underrepresented or excluded. | Covered-order definitions and executable-time rules capture more of these workflows.Source 2Source 3 |
| Fractional and odd-lot orders | Legacy size buckets were built around round lots. | Reports distinguish fractional, odd-lot and larger notional categories.Source 2Source 1 |
| Execution timing | Broad speed bands obscured very fast execution differences. | Time is measured at millisecond or finer precision.Source 2 |
| Public summary | Raw files were difficult for many users to interpret. | Each reporting entity must provide a summary report.Source 2Source 1 |
November changes the reference price
From 1 November, reporting entities must begin collecting the information needed to calculate price-improvement statistics against the best available displayed price. That benchmark compares the round-lot national best bid or offer with the best disseminated odd-lot price. November reports are due by the end of December.[3]
Why the benchmark can change the result
| Situation | Round-lot NBBO | Best odd-lot order | Rule 605 benchmark from November |
|---|---|---|---|
| Buy order | National best offer is $10.05 | Odd-lot offer is $10.04 | $10.04 is the better available displayed sell price.Source 3 |
| Sell order | National best bid is $20.10 | Odd-lot bid is $20.12 | $20.12 is the better available displayed buy price.Source 3 |
| No better odd lot | Round-lot quote is best | Odd-lot price is equal or worse | The NBBO remains the benchmark.Source 3 |
Consider the illustrative buy order above. An execution at US$10.04 is one cent better than the US$10.05 round-lot offer, but matches the better displayed odd-lot offer. The trade is unchanged; the benchmark determines how much price improvement the report records. That is why the November reference-price change matters when comparing results over time.[3]
Read the measures as a connected set
Metric and limitation
| Metric | What it measures | How to interpret it |
|---|---|---|
| Effective spread | Execution price relative to the midpoint at the relevant benchmark time. | Compare like orders and include separate fees when assessing the customer’s total cost.Source 2Source 3 |
| Realised spread | Execution economics after specified post-trade time horizons. | Read the specified time horizon; the measure is not a broker revenue statement.Source 2 |
| Time to execution | Elapsed time in millisecond-level categories. | Assess alongside achieved price, size and order conditions.Source 2 |
| Size improvement | Shares executed beyond the displayed quantity at the benchmark price or better. | Describes reported executions beyond displayed size; future liquidity can differ.Source 3 |
| Relative fill rate | How non-marketable orders filled relative to eligible market volume while executable. | Interpret against the particular order type and market-volume denominator.Source 3 |
A useful comparison holds the security, period, order type and size category as close as possible. A firm handling more small liquid-stock orders or a different stop-order mix can show different averages without the reports isolating the reason. Execution speed, price, fills and size together provide a more informative basis for questions about routing, charges and customer instructions.[1][3]
Expanded requirements began on 1 August 2026. Best-displayed-price collection begins on 1 November, making the first November report due at the end of December. The staff FAQ explains the implementation alongside the binding rule; it is staff guidance rather than a separate rule amendment.[1][3]
Sources & further reading
- Disclosure of order execution information: final rule and compliance extension US Securities and Exchange Commission · 30 Sep 2025 · Accessed 16 Oct 2026
- SEC adopts amendments to enhance disclosure of order execution information US Securities and Exchange Commission · 6 Mar 2024 · Accessed 16 Oct 2026
- Frequently asked questions: Rule 605 of Regulation NMS US Securities and Exchange Commission staff · 1 Apr 2026 · Accessed 16 Oct 2026