Reference

Methodology changelog

Version history of the SpotWire index methodology. Each entry documents what changed, when, and why. Methodology changes are dated and versioned so historical index values can be reproduced.

v0.6 — 2026-06-03/04 (current)

PRA hardening + multi-vendor sourcing

SWCI frontier component multi-sourced. The 35%-weight Frontier GPU OEM component was discovered to be 100% single-vendor (Supermicro via Thinkmate). Dell publishes no public frontier-node price (quote-only); CDW doesn't list frontier nodes. Two independent integrator sources added (Exxact, Bizon — B200/H200/MI300X configurator list prices). frontier_n_sources 1 → 3.
Single-source guard. New single_source_warning flag: fires when a component at ≥15% weight rests on fewer than 2 independent price vendors. Was true at introduction; cleared by the multi-sourcing. Permanent — if a vendor feed dies, the index re-flags itself.
Per-accelerator normalization. Frontier node prices now also published per accelerator (frontier_per_accelerator_value), commensurable with the per-card legacy GPU component. Rack-scale SKUs (GB200 NVL72) excluded.
Price-primitive disclosure (SWCI + SWII). Every component tagged with the kind of price it carries (ebay_transacted / oem_list / channel_list / cloud_quoted / stress_proxy). A list price is not a transacted price; the data now says which is which.
Condition-consistency (SWCI legacy GPU). The secondary GPU basket now assesses a consistent used-working spec, excluding premium (New/Refurb/Open Box) and parts/broken tiers. Measured effect −2% to +10% per SKU, direction varying — the prior mix was composition noise. Disclosed as gpu_condition_basis.
Source-tier relabel. frontier_gpu and nvswitch_oem relabeled tier_1_oem_direct → tier_2_integrator_channel_survey — OEM-direct frontier pricing is quote-only; what we survey is the integrator channel, and the label now says so.
SWII vendor-concentration guard + interconnect survey. New vendor_concentration_warning (fires at ≥40% single-vendor weight); correctly flagged FS.com at 60% at introduction. Three independent vendors added — ColfaxDirect (NVIDIA/Mellanox InfiniBand NDR/HDR/XDR at real part numbers), QSFPTEK, 10Gtek. Survey status is per-component and data-driven (≥2 vendors AND no vendor >75% of priced comps). All three former FS-only components now qualify; FS.com single-vendor exposure 60% → 0%. Per-component vendor shares published.
Open data. Per-index history CSVs (provenance-labeled rows), machine-readable methodology.json, frozen monthly archives, /cite formats, and stable issue permalinks (/v/I/{issue}).

v0.5 — 2026-06-02

Comp integrity + multi-year history

GPU comp composition cleanup. Secondary-market GPU ingest now excludes multi-unit lots, parts/non-working listings, and datacenter cards priced below a physical-implausibility floor. A100 80GB PCIe intra-window dispersion fell 8.55x → 4.29x — the median now tracks single working cards, not listing mix.
Multi-year sold-comp backfill. First-party transaction records extend GPU comp history to mid-2023 for key SKUs (A100 80GB PCIe: 5 months/19 comps → 25 months/74 comps). Backfilled rows are provenance-tagged and pass the same cleanup.
Cluster Valuator dataset. Per-SKU secondary medians + empirically measured vintage decay curves (A100 80GB PCIe ≈ −54%/yr, V100 32GB PCIe ≈ −36%/yr, H100 ≈ flat), cited condition/liquidation anchors, confidence bands, coverage-tier flags. Condition factors are cited anchors — eBay condition tags proved too noisy to derive them, and the methodology says so.
Depreciation cross-validation dataset. Disclosed accounting useful lives from 13 SEC filers vs SpotWire-measured secondary decay, with useful-life-change events and filing URLs as receipts.

v0.4 — 2026-05-29

Component weights for SWPI and SWFI revised to research-derived values with sensitivity analysis (RT-7)
Per-component n_comps (volume) now exposed in indices.json and on the public site (RT-11)
EDGAR text-mining lead-time regex widened — SWPI flips to LIVE (FU-1)
SEC EDGAR access refactored to use marketkit shared library

v0.3 — 2026-05-29

SWFI composite goes LIVE — first composite to drop the Indicative badge (P3-T8)
SWPI upgraded from spot-power-only to full diffusion (4/5 components active, P3-T5)
BLS PPI scraper covering 9 series across SWPI and SWFI cohorts (P3-T4, P3-T6)
EDGAR mining for SWFI cohort: Vertiv, Trane, JCI, Rockwell, Honeywell, Dover, Emerson (P3-T7)

v0.2 — 2026-05-28

SWCI compositor lands — first composite computed from real spot-desk data
Historical YoY backfill for SWCI basket: 71 source-attributed monthly points across 17 SKUs (P1-T7)
EDGAR mining for SWPI cohort: Quanta, MasTec, GE Vernova, Eaton, Hubbell (P3-T3)
EIA-860M, LBNL Queued Up, FS.com, gridstatus — five new data sources powering SWPI (P3-T1, P3-T2, P2-T1, P2-T4)
SSD pipeline unstranded; DDR5/DDR4 RAM scraper added to SWCI basket (P1-T1+T2)

v0.1 — 2026-05-27

Initial four flagship composite indices defined: SWCI, SWII, SWPI, SWFI
All four start as v1 hand-curated mock values, labeled Indicative
Variant-b website scaffolded; Substack subscriber form wired
Brand decision: spotwire.ai as primary; spotwire.io 301-redirects

Corrections policy

Material corrections (any change to a previously-published index value of ≥1%) are announced via the weekly newsletter, on this changelog page, and via a homepage notice for one week.
Non-material corrections (typos in methodology docs, minor recompute differences below 1%) are silently corrected and noted in the next changelog entry.
Methodology changes that affect future values are dated and versioned. Historical values published under prior methodology are NOT retroactively re-computed; the index value as-of-its-publish-date is canonical.
Errata affecting more than 5% of a published value require an explicit "Correction" entry above the affected index card on the homepage for two weeks.

Reproducibility

Each weekly indices.json export is archived at data/web_export/indices_YYYY-MM-DD.json in the spot-desk repository. Methodology versions on this page map to dated entries; future releases will tie each version to a git tag for byte-reproducible historical reconstruction.