The tracked universe and comparable sets
Who exactly is in this site's manager universe, and why counts are always labeled with it.
Roughly nine thousand managers file 13Fs each quarter. This site indexes filing metadata for all of them — every filer is searchable, with its filing history — and parses full position-level holdings for a tracked universe: the largest managers by reported value plus a curated set of prominent investors, several hundred in all, with deeper history for the curated set. The site header and every aggregate page show the live counts.
Why not parse everyone?
Position-level analytics on the long tail of small filers adds noise faster than information: a $120 million adviser's 40 positions move aggregate statistics without describing institutional behavior. The tracked universe covers the overwhelming majority of reported 13F value while keeping every derived statistic auditable. Where a page shows full-market context (holder counts across all filers from the SEC's structured data), it is labeled as such and carries its own as-of period.
Comparable sets
Quarter-over-quarter comparisons only use managers observed in both quarters — otherwise a newly tracked manager would appear as phantom "buying." During filing season, aggregates additionally restrict to managers whose new filing has arrived. This is why pages say things like "among 214 comparable managers": the number is part of the claim. The data-pipeline methodology documents the rules, and the season page shows how much of the universe has reported at any moment.