Investor Holdings: Following the Funds Who Actually Know the Name

Why Studying a Single Investor's Book Is Different From Scanning 13Fs

The generic 13F surface — "who bought NVDA last quarter?" — is a ticker-first question. The inverse question — "what does Appaloosa's entire book look like today?" — is an investor-first question, and it's far more educational. Tepper's, Burry's, Buffett's, and Einhorn's books read like pedagogy for portfolio construction: how much to diversify, when to concentrate, how to express a sector view, how to use options. The Investor Holdings card is built for the investor-first view.

What the Investor Holdings Card Shows

The Investor Holdings card lists every position in a filer's most recent 13F with: position size (shares + market value), % of reported AUM, % change vs prior quarter (new / add / trim / exit), sector, and cost basis estimate (blended average of transaction ranges since initial purchase). The table is sortable and filterable; a sector-weight donut and a top-10 concentration bar quickly show how diversified the book is. A "conviction positions" filter surfaces holdings sized >3% of AUM that have survived at least 4 quarters — the portfolio's actual convictions, as distinct from experimental trades.

Reading a Book

Three reads are the most useful. First, top 10 / AUM concentration — under 20% means a diversified manager (typical of long-short funds); 30-50% is a concentrated long-biased book (Baupost, Appaloosa); 70%+ is a single-bet shop (Pershing Square, Scion). Match your study to managers whose style matches yours. Second, new positions sized at >2% on day one — this is a signal the manager moved in aggressively after doing work; these are often more studyable than existing positions. Third, exits of former conviction positions — when a name that was top-10 for 8 quarters leaves the book entirely, something changed in the thesis; 13F exits are a cheap research prompt.

Where It Fits

Pair with Investor Diff for the quarter-over-quarter change view across filers, with Institutional Holders for the per-ticker cross-filer read, and with 13F source docs for raw filings.

Open the Investor Holdings card → /app/investors