Datum reference rates, version 1.0.
The method, in the order it runs. The full document is published here, versioned, with a changelog. Sections marked in review are being finalized.
DATUM-B200: on-demand composite. DATUM-B300: term and on-demand. DATUM-GB300: term. Unit is USD per GPU-hour, per chip, per tier, never blended across chips or tiers. Underlying per-tier series carry the id DATUM-{CHIP}-{TIER}.
in review: final series list and tier codes from the index lane
Every observation carries a provenance class: listed (public list and marketplace rates observed daily), contributor (rates submitted under a panel agreement), metered (attested realized rates), licensed-third-party (an third-party settle consumed under license, cited by source and provenance-tagged, never silently blended). Panel composition by class is published with every print.
in review: source list per series and the licensed-third-party terms
Composite series combine a licensed third-party settle (level) with the Datum live listing panel (intraday path). Weights are fixed per method version and published. Freeze rule: if a required input is missing or stale beyond its window, the composite freezes to the last good print and flags it. A composite never degrades into a list-price index without a method version change.
in review: weights per series and the exact freeze window (36h proposed)
Eligibility runs in order: scope, unit, staleness, duplicate, then dispersion. Observations older than 48 hours are dropped. Within the eligible set the print is the median; observations beyond 2.5 MAD from the median are dropped and logged. Minimum panel size is 3, otherwise the series prints as insufficient panel and does not carry a value.
Daily fixing at 16:00 ET on the eligible panel as of the cut. Hourly mark between fixings on the same method with a time-weighted window and a clamp against the last fixing, so the mark cannot move faster than the panel supports.
in review: TWAP window and clamp width for the mark
Each fixing is a versioned artifact: series, date, value, panel size, panel by class, method version, inputs hash, dropped observations, signer. The artifact is signed and its content hash is anchored on Base. Any published print can be recomputed from the artifact and checked against the chain. The contract address is published here once deployed.
A print is never overwritten. A correction is a new artifact that references the one it supersedes; both stay published and anchored, and the lineage is visible in the api.
Method changes bump the method version. Prints carry the version they were computed under. Series computed under a method that has not completed review carry an -unofficial suffix and are labelled as such wherever they appear. Chip generation rolls (Blackwell to what follows) are handled by a published roll rule, not by redefining a series in place.
in review: roll rule text
v1 inputs are observed listed rates plus a licensed third-party settle; not a transaction index. Panels are thin on the newest chips and the panel size is printed so the reader can judge it. Reference grade, not settlement grade, until cleared prints dominate the panel.