---
title: "Per-contract volume vs rolling baseline (unusual options activity)"
method: GET
path: "/api/v1/options/{symbol}/unusual-volume"
tags: ["Options"]
---

# Per-contract volume vs rolling baseline (unusual options activity)

`GET /api/v1/options/{symbol}/unusual-volume`

Derived endpoint that flags contracts whose current per-contract volume materially exceeds the contract's own rolling average across the last ``baseline_window_days`` dated snapshots. Walks the latest B6 snapshot's per-contract volumes; for each contract (both calls and puts) computes ``baseline_avg = mean(volume across days the contract appeared with positive volume)`` and flags rows where ``current_volume / baseline_avg > threshold``. Per-row output carries OSI contract symbol + strike + expiry + current volume + baseline + ratio + supplementary Greeks (delta + IV). Sorted by ratio DESC; truncated to ``limit``. Use case: ``UC-4 Insider + Options Flow Confluence`` - bullish skew detection in concert with Form 4 insider purchases.

## Path parameters

- `symbol` string, required — Underlier ticker.

## Query parameters

- `threshold` number — Volume-ratio threshold for the unusual flag (1.5..50). Default 3.0 = 3x the contract's rolling average.
- `limit` integer — Maximum flagged contracts returned (1..200).
- `baseline_window_days` integer — Rolling baseline window in calendar days (5..90). Defaults to 30. Bounded by 90-day retention.
- `min_volume` integer — Minimum current-snapshot volume for a contract to be evaluated (filters illiquid deep-OTM strikes).
- `min_baseline_days` integer — Minimum baseline coverage (days the contract appeared with positive volume) required for a contract to qualify. Contracts below this floor land in contracts_excluded_no_baseline.

## Response `200`

Unusual options activity payload.

- EnvelopeOptionsUnusualVolumePayload
  - `data` OptionsUnusualVolumePayload, required — UC-4.5 derived endpoint: contracts with current volume well above their own recent average. Walks the latest B6 snapshot's per-contract volumes and compares each contract to a rolling baseline computed across the last N dated snapshots. Contracts where `current_volume / baseline_avg_volume` exceeds the threshold are flagged; results sorted by ratio DESC. Methodology limits (v1): - Baseline uses per-contract volume on days where the contract was present with positive volume. Contracts that didn't exist (newly- listed) or had zero volume on some days contribute a SHORTER baseline_days_count but still get a baseline_avg over the days they had volume; `min_baseline_days` query param controls the minimum coverage for a contract to qualify. - `current_volume` floor (`min_volume` query) filters noise from sparsely-traded deep-out-of-money strikes. - Daily granularity from B6 snapshot cadence — no intraday volume bursts captured. - PUT and CALL both included (this is a volume-burst signal, not a direction signal); callers can filter by `option_type` client-side.
    - `symbol` string, required
    - `snapshot_date` string, required
    - `underlier_price` number, nullable
    - `threshold` number, required — Echoed ratio threshold; contracts with volume_ratio > threshold are flagged.
    - `baseline_window_days` integer, required — Echoed baseline lookback window.
    - `baseline_snapshots_loaded` integer, required — Actual count of historical snapshots loaded for the baseline (≤ baseline_window_days; less when ingest hasn't filled the full window yet).
    - `min_volume` integer, required — Echoed current-volume floor.
    - `min_baseline_days` integer, required — Echoed minimum baseline-coverage floor.
    - `contracts_evaluated` integer, required — Contracts in the latest snapshot considered after floors applied.
    - `contracts_excluded_no_baseline` integer, required — Contracts excluded because baseline_days_count < min_baseline_days.
    - `unusual_count` integer, required — Contracts whose volume_ratio > threshold.
    - `unusual_contracts` OptionsUnusualContract[], required — Flagged contracts sorted by volume_ratio DESC then current_volume DESC.
      - `contract_symbol` string, required — OCC OSI contract symbol from the snapshot.
      - `option_type` string, required — C for call, P for put.
      - `strike` number, nullable
      - `expiry` string, required — Expiration date (YYYY-MM-DD).
      - `current_volume` integer, required — Today's contract volume (current snapshot).
      - `baseline_avg_volume` number, required — Arithmetic mean of contract volume across the baseline window days where the contract appeared with positive volume.
      - `baseline_days_count` integer, required — Number of historical days the contract was found in the baseline window (max = baseline_window_days). Lower count = weaker baseline.
      - `volume_ratio` number, required — current_volume / baseline_avg_volume. Higher = more unusual relative to the contract's own recent average.
      - `open_interest` integer, nullable
      - `implied_volatility` number, nullable
      - `delta` number, nullable
      - `in_the_money` boolean, nullable
    - `data_source` string, nullable — Provenance of the underlying B6 snapshot blob. Exchange-direct options for VIX (live, native Greeks). Legacy commercial equity options path for ~199 equity underliers - stale-by-design since DATA-N1 disabled that ingest. Compare ``as_of`` against today to gauge freshness. Wire tokens are stable identifiers, not brand names.
    - `as_of` string, nullable — ISO-8601 timestamp of when the underlying snapshot blob was taken (``snapshot_taken_at`` in the blob). For DATA-N1-skipped underliers this is the last good upstream cycle before disable.
  - `meta` SugraMeta, required — Metadata on a /api/v1/* response envelope built through `helpers.response.sugra_response`, which is how routes are expected to answer. A route that assembles its own `meta` dict carries only the keys it writes itself, so an optional field below can be absent because this response has nothing to report OR because that route does not build its envelope here - the two are not distinguishable from the outside (API-43).
    - `endpoint` string, required — Requested endpoint path.
    - `data_time` string, required — ISO 8601 timestamp the data on this response is stamped with. It is the source's own timestamp whenever the source supplied one this API could read; when it did not, this field falls back to the value of `response_time` and `data_age_days` is omitted, so the PRESENCE of that field is the signal to read - with the one exception named in its own description, a route that substitutes its own current time for a source timestamp it never received. Usually UTC (`Z`), but a source stating its own numeric offset keeps it (2026-04-16T14:30:00+09:00) rather than being converted a second time. For a source that publishes by period this is the period's START (see `period`) and for one that publishes by calendar day it is that day's midnight - in neither case a moment at which anything was observed or released.
    - `response_time` string, required — ISO 8601 UTC timestamp when this response was produced.
    - `provider` string, required — API name and version.
    - `data_age_days` number, nullable — Age of the data in days at the moment this response was produced, i.e. `response_time` minus `data_time`. Present ONLY when the timestamp this response is stamped with is a clock time that could be read as a real instant. It is ABSENT - never 0 - in every other case. Absent when no readable source timestamp was supplied, because `data_time` then repeats `response_time` and a zero age would assert that the data is current precisely where its true age is unknown. Absent when the source names a calendar day, a month, a quarter or a year (see `period`): the instant is then a boundary this API anchored at midnight, and time since a day or a quarter BEGAN is a different quantity from the age of the data - a daily series is out by up to a day, a quarterly one by up to a quarter. A midnight counts as such a boundary whichever zone it is stated in, and whether the source stated it or this API anchored it. The one case this field cannot see is a route that substitutes its own current time for a source timestamp it never received: the substituted value is a real, readable instant and is indistinguishable from one the source stated, so the age reads as roughly 0. The shared cache-and-fetch helper behind most routes stopped doing that (API-43), but the presence of this field is a statement about the timestamp the response carries, not a guarantee about the route that supplied it. Rounded to 0.001 day (86.4 seconds), so 0.0 is a real measured age anywhere within roughly +/-43 seconds and not a stand-in for unknown; a source stamping an instant in the future reports a negative value (-0.001 or less) rather than being clamped. Sources publish on very different cadences, so a non-zero age is normal, not an error. Preserve absence in client code: a generated client that materialises a missing optional number as its numeric default turns 'age unknown' back into 'age zero', which is the exact confusion this field exists to remove.
    - `source` string, nullable — Identifier of the primary upstream source used for this response.
    - `attribution` string, nullable — Human-readable attribution mandated by an upstream source (e.g. a securities regulator or self-regulatory organization). Present only on responses whose source requires the owner and source to be clearly identified. Do not remove or alter it when using the response.
    - `fallback_used` boolean, nullable — True when the primary source failed and a fallback produced the data.
    - `fallback_chain` string[], nullable — Ordered list of sources attempted, in the order they were tried.
    - `cached` boolean, nullable — True when this response was served from the internal cache.
    - `stale` boolean, nullable — True when the response is known stale under its source freshness policy, or when a cached response was returned after the upstream rate-limited or errored. Clients can use this to detect degraded data.
    - `stale_since` string, nullable — ISO 8601 UTC timestamp of the last good copy this response was served from. Present only when stale is true.
    - `period` string, nullable — Unit of observation, when the source publishes by period rather than by instant. `data_time` carries the period's START instant so it stays machine-readable; this field preserves what that instant used to mean, which the conversion would otherwise erase. Present only for such sources, and only when the source hands the API the label itself - a client that converts the period to its start instant before building the envelope loses the label, though not the age exclusion, which is decided by the instant. Note that `data_age_days` is omitted whenever this is present, because an age measured from a period start is not a freshness figure.
    - `notes` string, nullable — Data-quality caveat about THIS response - how old the underlying report is, a chokepoint AIS lower-bound, or that a source-reported `data_time` could not be read and the response time is shown instead. Distinct from `attribution`, which is a licensing obligation. Multiple caveats are joined with ' | '. Present only when there is one.

## Other responses

- `401` — Missing or invalid `x-api-key` header. JSON body with a stable `code` distinguishing `missing_api_key` (no header sent) from `invalid_api_key` (header sent, key not accepted); any other 401 source carries the generic `unauthorized` with its detail as `reason`. Plus `hint`. `plan` is always null on 401 - an unauthenticated request has no plan; quota exhaustion is 429, not 401.
- `422` — Validation Error
- `429` — Daily rate limit exceeded. Check `X-RateLimit-Reset` for the next window.
- `500` — This API answered a shape its own schema refuses. Typed body `error: response_shape_invalid`. Stays a 500 (WEB-28). Not an upstream failure.
- `503` — Upstream source is temporarily unavailable. Retry after a short delay.

## Changes

> 33 revisions in range; 1 not diffed.

- **2026-09-13** `d2472ec2cf81` — 1 info
  - added the non-success response with the status `500`
- **2026-09-09** `4f8853a61440` — 1 info
  - added the optional property `meta/stale_since` to the response with the `200` status
- **2026-09-01** `328d061c12ca` — 3 info
  - added the optional property `meta/data_age_days` to the response with the `200` status
  - added the optional property `meta/notes` to the response with the `200` status
  - added the optional property `meta/period` to the response with the `200` status
- **2026-08-08** `4c4530760ba1` — 12 info
  - added the optional property `code` to the response with the `401` status
  - added the optional property `code` to the response with the `429` status
  - added the optional property `code` to the response with the `503` status
  - added the optional property `hint` to the response with the `401` status
  - …8 more

[Change history](https://skmtc.dev/sugra/apis/sugra-api/changes/api/v1/options/:symbol/unusual-volume/get.md)

---

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