Observed market data · immutable monthly snapshot

Birkin Resale Market Dataset & Methodology

This dataset freezes a point-in-time observation of publicly indexed Hermès Birkin resale asking prices. It is not a transaction-price feed, market census, appraisal, authentication result, or guarantee that a listing remains available.

3,889Observed unique listings
3,888USD-priced cohort n
$25,995Median observed ask
22Indexed merchants
24/27Sources recently observed
2026-08-09.v1Methodology version

Snapshot 2026-08 was generated 2026-08-08T23:21:52.610428+00:00. “Observed” means the listing appeared in the public index; it does not mean BirkinBagStock authenticated or independently verified the item or merchant.

What this snapshot covers

Public Hermès Birkin resale listings observed in the BirkinBagStock index at the snapshot timestamp and aggregate asking-price statistics for eligible USD rows.

It does not represent

  • completed transaction prices or sales volume
  • a census of the entire resale market
  • an appraisal or investment return
  • authentication or independent verification of an item or merchant
  • continued availability after the snapshot timestamp

Coverage & exclusions

Input rows3889
Unique listing IDs3889
Eligible USD asks3888
Missing observation timestamp3889
Excluded from price stats1
Converted before ingestion0

Rows excluded from USD price statistics can remain in observed listing counts; this prevents a missing, non-positive, non-finite, or non-USD ask from distorting price cohorts.

Methodology

  • Unit: one unique public listing ID at snapshot time.
  • Price: merchant asking price stored in USD; not a transaction price.
  • Deduplication: Rows are deduplicated by listing ID. If an input repeats an ID, the row with the latest available observation/update timestamp is retained with a deterministic tie-break.
  • Price inclusion: A row enters price statistics only when its ask is finite, greater than zero, and its reporting currency is USD.
  • Percentiles: P25, median, and P75 use the closest observed value at floor((n-1)*p+0.5) after ascending sort.
  • Cohorts: Cohort observed_n counts unique listings carrying the dimension value; priced_n counts the USD-price subset.
  • Completeness: Per-source scraper health is disclosed separately. Only feeds explicitly marked verified_complete have product-grade completeness evidence; observed_unverified feeds are not treated as exhaustive.
  • Revisions: The first successfully persisted snapshot for a UTC month is immutable. Corrections require a new methodology version and explicit publication path.

FX treatment

Some source adapters convert merchant prices to USD during ingestion and preserve original_price and original_currency. This snapshot uses the stored USD ask and does not independently refresh, reconstruct, or audit the adapter FX factor. Non-USD reporting rows are excluded.

Inclusion rule: Only positive finite asks stored with reporting currency USD are analyzed.

Source status

Source status is the latest scraper observation available at snapshot time. Observed does not mean authenticated, independently verified, exhaustive, or still available.

Verified-complete sources0
Observed sources24
Degraded sources3
Error sources0

Citation & integrity

BirkinBagStock, "Observed Birkin Resale Market Snapshot — 2026-08", methodology 2026-08-09.v1, generated 2026-08-08T23:21:52.610428+00:00, https://birkinbagstock.com/data/market-snapshots/2026-08.json.

Aggregate snapshot may be cited with attribution. Underlying merchant listing content, images, availability, prices, and terms remain subject to their source owners and must be rechecked.

SHA-256 checksum

29dd1829d23624ca7da660e1324072064ce87a94e9270ade7c9534282eecfdca

The checksum covers canonical UTF-8 JSON with sorted object keys and compact separators, excluding the checksum field itself. This makes later mutation detectable even if JSON whitespace changes.

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