Methodology

The provenance rule

Every value shown on stonks traces to its primary source: the exact SEC filing (accession number), the agency release, or the API request that produced it — plus the date we fetched it (its vintage). If a number can’t show its receipt, it doesn’t ship. There are no hand-entered values anywhere in the system.

Sources, agency-direct

Macro series come straight from the publishing agencies — U.S. Treasury (par yield curve, Debt to the Penny), the New York Fed (EFFR, SOFR), the Bureau of Labor Statistics (CPI, employment), the EIA (energy), the BEA (GDP), and the World Bank (global indicators, CC BY 4.0). Fundamentals come from SEC EDGAR company facts — the structured XBRL data companies themselves file. We do not scrape other data websites. The full registry, with licenses, is on the sources page.

Vintages, not overwrites

Economic data gets revised; restatements happen. Our observation store is append-only: when an upstream value changes, we insert a new vintage alongside the old one rather than overwriting history. Pages show the latest vintage and say so; prior vintages stay queryable. This is how you can trust a chart and audit it.

Normalization, in the open

Fundamentals are normalized from raw us-gaap tags with published fallback chains (for example, revenue prefers RevenueFromContractWithCustomerExcludingAssessedTax and falls back to Revenues). The winning tag is recorded on every value and shown in the financials table on hover. A missing tag means a missing cell — never a silent zero. Derived values (free cash flow, YoY changes, indexed series) record their parents and formula in a transform lineage.

Anomaly gates

Ingestion refuses to publish series that fail sanity checks — empty results, malformed or duplicated dates, non-finite values, or suspicious single-step jumps in level series. Failed checks land in an error log, not on your chart. New series stay unlisted until they accumulate enough history to be meaningful.

Corrections, in public

When we get something wrong, the fix is logged on the corrections page— what was wrong, when it was discovered, and what changed. An error corrected quietly is an error you can’t trust us about.

For machines

The same provenance-tagged data is free for AI systems and programs: a JSON API at /api/v1 and an MCP server at /api/mcp, both returning source metadata with every value. Attribution required; see about.