WMTMT (what moved the market today) decomposes every move of the S&P 500, the Dow Jones Industrial Average, the Nasdaq-100, and the eleven SPDR sector indices into per-stock point contributions. When an index rises 54 points, WMTMT shows which stocks contributed which of those points, how many members participated, and how concentrated the move was. The daily market-close note publishes minutes after each session ends; a weekly review follows on Fridays.
How the engine works
Each index is reconstructed from its members' prices under the index's own arithmetic: price-weighted for the Dow, float-adjusted cap weights derived from daily ETF holdings for the rest. The reconstruction is checked against the official closing level before anything publishes, and the residual is disclosed on every page. Intraday views are rebuilt from members' latest trade prices and marked unofficial until the close. The concepts are documented plainly in How to read the numbers, and each day's verified figures are available as structured data through the public endpoints.
Authorship
The daily notes are compiled by the WMTMT attribution engine: software that assembles each session's verified numbers and drafts the note under strict rules. It may only cite figures present in the day's data, it does not speculate about causes, and it makes no predictions and gives no advice. Every note is labeled accordingly. WMTMT is built and edited by the founders of Babylon Burns, whose letter carries the human arguments; the two publications are separate, and subscribing to one never adds you to the other.
Corrections
If a published figure fails a later check against official data, the note is regenerated from corrected data and replaced in full, and its images are re-rendered from the same corrected data. The reconstruction gates exist so this is rare: a session that cannot be verified against its official close is not published until it can be.
Contact
Reach us through the WMTMT Substack or Babylon Burns. Data sources are credited in the footer of every page. Nothing on this site is investment advice.