Stop Comparing Berkshire to Vanguard — How Filer Groups Make 13F Analysis Actually Useful

Comparing Berkshire Hathaway's portfolio to Vanguard's is like comparing a restaurant's menu to a grocery store's inventory. They serve completely different purposes. Yet this is exactly what most people do with 13F data — compare managers without considering that they have fundamentally different mandates, strategies, and constraints. Filer groups fix this problem. What filer groups are A filer group is a curated set of 13F filers that share similar characteristics — strategy type, AUM range, investment style, or institutional category. Instead of comparing all 6,000 filers against each other, you compare within groups where the comparison is meaningful. Why random comparisons fail Comparison Why it's misleading Berkshire vs. Vanguard Concentrated active value vs. passive index — completely different objectives ARK vs. Bridgewater Thematic growth vs. macro all-weather — different universes Jane Street vs. Dodge & Cox Market maker vs. value investor — one is hedging, the other is inves