MIAX Emerald has taken a meaningful step toward making more granular, trade-level historical options data available to subscribers: it filed a rule change (SR-EMERALD-2026-14) to establish a purchasable Trade-by-Trade Report, and the SEC published the notice as Release No. 34-105507.
The key nuance is timing. The SEC notice indicates the rule change became operative upon filing (the SEC waived the normal operative delay), but MIAX separately says it is targeting a commercial launch in the second or third quarter of 2026 and plans to announce actual availability in a future alert. In plain English: the regulatory plumbing is in place, but the product is not necessarily live for subscribers yet.
Non-advice notice: This article is for general information and education only - not financial advice, not investment advice, and not a recommendation to buy or sell anything. Options trading involves risk and is not suitable for all investors. See the site’s Risk Disclosure.
If you want a quick refresher on why “open interest” is easy to misread, start here: What is open interest in options?.
What Happened (Confirmed)
Based on MIAX and SEC materials:
- MIAX Emerald filed SR-EMERALD-2026-14 to amend Rule 531 and establish a new Trade-by-Trade Report as an optional, fee-based market-data product available to Members and non-Members.
- The SEC published Release No. 34-105507 describing the proposal and the filing pathway (immediate effectiveness framework with a waived operative delay).
- MIAX states the report is T+1 historical data (available overnight after midnight Eastern), not real-time.
- MIAX states it is targeting Q2 or Q3 2026 for launch and will issue an alert when subscribers can access the report.
What The Trade-by-Trade Report Is (And What It Is Not)
At a high level, MIAX is describing a file designed for next-day reconstruction of what happened on MIAX Emerald:
- Each row is intended to represent one side of a single trade event.
- The report includes the option terms (underlying, expiration, strike, put/call), execution details (quantity, price, side), and a set of context fields intended to make interpretation less guessy.
This is not positioned as a “smart money feed” or a live order-flow tool. The exchange’s own description is deliberately historical: you get detail after the session, not while the tape is moving.
What Information Is In The File (Key Fields That Matter)
MIAX’s confirmed field list includes (in MIAX’s phrasing) trade date/time and identifiers, option terms, pricing/size, and several “why did this print look like that?” context flags. For traders, the fields that matter most tend to fall into a few buckets.
1) Open/close indicators (context for open interest narratives)
Many retail interpretations of unusual options activity assume “big volume = new bullish positioning” or “big put volume = new bearish positioning.” The open/close indicator is one of the few fields that helps separate:
- opening activity (potentially creating new exposure), from
- closing activity (potentially reducing or transferring exposure).
Even with this field, be careful: one side can be opening while the other is closing, and open interest is a clearing-based calculation that updates later. Treat open/close as helpful context, not a standalone directional conclusion.
2) Origin (who the trade was from, in a coarse way)
The report includes an “origin” field (as described in the filing materials). In practice, origin classifications are often used to distinguish broad participant types (for example, customer vs professional vs firm/market maker categories, depending on the venue’s schema).
This can help reduce false stories, but it does not turn a venue-specific print into a universal “institutional” tell.
3) Segment codes (auctions, crosses, complex, routed, and other microstructure context)
MIAX’s filing materials reference a trade segment code and give examples such as:
- opening/reopening auction
- routed
- simple vs complex
- PRIME / cPRIME
- QCC
Why this matters: an auction print or contingent cross can be mechanically different from a trader “hitting the bid” because they are bearish. Segment labels are one of the cleanest ways to avoid mixing microstructure with narrative.
4) Market context fields (NBBO vs local book)
The report includes market-context indicators such as NBBO and EBBO (exchange best bid/offer). This is especially useful for execution review:
- Was the trade executed at (or through) the national market?
- Was it inside/outside the venue’s local best?
- Was the trade happening in a wide, stressed, or thinly quoted context?
This is not “alpha” by itself, but it is practical for spotting when a fill was likely constrained by spread/tick regime and venue conditions.
5) Penny vs non-penny class (tick-size regime)
MIAX highlights a penny/non-penny indicator as a differentiator versus some comparable products. Tick regime matters because it affects what “good execution” even means. A one-cent environment and a wider-minimum-variation environment produce different spread behavior and different expectations for price improvement.
6) Identifiers that help link complex activity
MIAX indicates the report includes a complex trade ID and a transaction ID. The reason traders should care is simple: it helps distinguish true single-leg activity from multi-leg spreads, rolls, and other linked executions that can make one strike look “unusually active” when it is only one leg of a package.
Why This Matters For Options Traders
The practical value here is less about prediction and more about better explanations.
Next-day interpretation of unusual prints becomes less guessy
If you scan for unusual options volume, a trade-by-trade file with open/close, origin, and segment context can help answer: “What did that print likely represent?” without defaulting to the most dramatic story.
Execution-quality review gets more grounded
For traders who care about slippage (especially frequent rollers, short-dated traders, and spread traders), the combination of trade context fields and market context fields can help identify:
- when a fill was likely constrained by a wide market or tick-size regime, and
- when a print came from an auction/cross mechanism rather than plain book interaction.
It encourages better discipline around volume vs positioning
Volume is easy to see. Positioning is harder. A T+1 file does not solve that problem, but it can reduce overconfidence by making it easier to spot when “big volume” was actually complex-linked activity, a cross, a closing flow, or something that does not map cleanly to a directional bet.
Key Limitations (And What We Still Do Not Know)
The filing clarifies several limitations traders should internalize:
- Not real time: MIAX describes the report as T+1 historical data available overnight after midnight Eastern.
- Not whole-market: it covers trades executed on MIAX Emerald, not the entire U.S. options market.
- Pricing is not yet published: MIAX indicates it plans to submit a separate fee filing later, and the current fee schedule reviewed for this report does not list this product.
- Full taxonomy/spec is not fully public in the rule text: MIAX references a separate specification users can request for complete category lists and row details.
- Backfill depth is unclear: the rule text does not clearly state how much historical data will be available at launch.
- “Operative” does not equal “available”: MIAX still describes the launch window as Q2 or Q3 2026, with a future alert for subscriber access.
What Traders May Misunderstand
Misunderstanding #1: “This is a live order-flow signal.”
No. It is explicitly framed as historical T+1 data delivered after the session.
Misunderstanding #2: “This covers the whole U.S. options market.”
No. It covers transactions executed on MIAX Emerald, even if it includes national market context fields.
Misunderstanding #3: “A big call print means bullish opening flow.”
Not necessarily. Without open/close context (and later, open interest changes), volume alone is not a reliable positioning signal. Even with open/close, the safe stance is “more context, not certainty.”
Misunderstanding #4: “QCC, PRIME, and complex prints are just directional bets.”
Not necessarily. Segment codes exist because there are structurally different execution mechanisms; interpreting every print as a simple directional trade is a fast way to be wrong.
Misunderstanding #5: “This changes assignment risk.”
No. Assignment is governed by exercise decisions and OCC/broker processes. This report may improve post-trade visibility, but it does not change options mechanics.
Practical Ways To Use A T+1 Trade-by-Trade File (No Trade Recommendations)
If you do get access to a report like this, the safest and most productive workflow is “interpret, then verify”:
- Start with a question, not a conclusion. Example: “Was that large print likely opening exposure, closing exposure, or a spread/roll leg?”
- Use the IDs to avoid single-leg overreads. Complex-linked identifiers can help you avoid treating a spread leg as a standalone conviction trade.
- Use segment codes to separate mechanisms. Auction/cross labels can explain pricing that looks odd compared to a quick NBBO snapshot.
- Review execution context, not just size. Market context fields help frame what was realistically fillable.
- Cross-check with next-day open interest (when relevant). Open interest updates are not instantaneous; use OI as confirmation context rather than forcing a story from volume.
Bottom Line
MIAX Emerald’s Trade-by-Trade Report proposal is a meaningful market-data upgrade for next-day forensic analysis of options executions on that venue: more trade-level detail, better linkage for complex activity, and more microstructure context than aggregated open/close summaries. The most important caveat is timing and interpretation: the SEC notice makes the rule change operative, but MIAX still targets a Q2 or Q3 2026 commercial launch, and the data is delayed by design. Treat it as a tool for better explanations and execution review, not a real-time signal and not a trade recommendation engine.
Sources
https://www.sec.gov/files/rules/sro/emerald/2026/34-105507.pdf- SEC Release No. 34-105507 (primary notice for SR-EMERALD-2026-14; operative status and timing statements).https://www.sec.gov/files/rules/sro/emerald/2026/34-105507-ex5.pdf- SEC Exhibit 5 (rule text excerpts and field list context).https://www.miaxglobal.com/markets/us-options/emerald-options/rule-filings- MIAX Emerald rule filings page (exchange-side posting of SR-EMERALD-2026-14).https://www.miaxglobal.com/markets/us-options/emerald-options/reports- MIAX Emerald reports page (context on current report offerings and access workflow).https://www.miaxglobal.com/sites/default/files/fee_schedule-files/MIAX__Emerald__Fee__Schedule__04012026.pdf- MIAX Emerald fee schedule referenced for “fees not yet listed” check.https://www.miaxglobal.com/miax_emerald_exchange_rules.pdf- MIAX Emerald rulebook (definitions referenced for NBBO/EBBO, penny classes, QCC, PRIME).https://www.optionseducation.org/news/open-interest-why-it-matters- OIC explainer on open interest mechanics (used for non-predictive framing).https://www.optionseducation.org/referencelibrary/faq/options-assignment- OIC/OCC assignment FAQ (used to clarify assignment mechanics are unchanged).
