13F Filing
Also called: 13F, institutional holdings report
A 13F discloses the US equity holdings of institutional managers with over $100m, filed quarterly within 45 days of quarter end. It's the basis of every article about what famous investors are buying, and it has real limits: it's stale by up to 135 days, excludes short positions, bonds and non-US holdings, so the picture it paints is both delayed and partial.