Where this database becomes research.

• Research, not commentary. Every letter starts from something unusual in our own data — a divergence, a regime change, a chart that looks scary — and does the homework in public: what the full history says, what survives scrutiny, and what doesn't. When the honest answer is “this famous signal doesn't work,” that is the letter.
• Numbers you can check. Every chart is computed from the same public datasets that power this site, date-stamped, with a link to the live version that updates after each close. Nothing is asserted that you can't verify yourself.
• Falsifiable markers. Each letter ends with the specific, watchable conditions that would confirm or kill its thesis — and when a marker moves, the follow-up letter is how you hear about it.
• No fixed schedule, no filler. Letters ship when the data hands us something worth your inbox — typically a few times a month, never on a content calendar.

The site is the instrument panel: every tool updates daily, shows its full history, and explains its methodology — free, no signup. The letter is the narrative layer on top — which instruments are disagreeing right now, what that has meant historically, and what would change the read. If you only want the data, the site is enough. If you want to know what we think it means, that lives in the letter.

Recent letters have covered the Nasdaq's divergence from the S&P 500 across five independent gauges, and why the scariest breadth chart in our database — the Nasdaq's cumulative TICK, which peaked 16 days before the 2021 top — mostly doesn't predict what it looks like it predicts. Browse the full archive on Substack.

Yuriy Matso — the same person who builds and maintains this site, its data pipeline, and its methodology. The letter carries the site's editorial standards: dated claims, primary sources, corrections on the page, and transparent AI usage. It is research and education, never financial advice.