Notes from OpenStocks
Essays on reading institutional portfolios, insider trades, and Congressional disclosures without getting fooled — plus changelog notes and product deep-dives.
Why we built OpenStocks
2026-04-19 · 4 min readAn open-data alternative to closed financial dashboards — built directly on SEC EDGAR and disclosures.house.gov.
metaopen-dataHow to read a 13F filing without getting fooled
2026-04-15 · 7 min read13Fs are a useful sentiment signal — and a deeply misleading data source. Here's how to read them like a pro.
13FresearchCluster buying: the one insider signal that actually works
2026-04-10 · 6 min readMost insider transactions are noise. But when three or more insiders buy in the open market within 30 days, the signal is real.
insidersForm 4signalsWhat the STOCK Act actually requires (and where it falls short)
2026-04-05 · 5 min readMembers of Congress have to disclose stock trades within 45 days. The disclosures are public, but the format is hostile and enforcement is weak.
congressSTOCK ActSuper-investor portfolios, explained
2026-03-30 · 6 min readBuffett, Burry, Pabrai — what the 13F portfolios of legendary investors actually look like, and how to read them without copy-trading.
13Finvestors