13F filing

A 13F is a quarterly report that any institutional investment manager overseeing more than $100 million in securities must file with the SEC, disclosing most of their US equity holdings as of the last day of the quarter. It's filed within 45 days after each quarter closes, and it covers the full range of institutional managers, hedge funds, mutual funds, pension funds, and any other entity crossing that asset threshold, rather than a curated shortlist of well-known names.

Read 13F data by change type rather than the raw holdings snapshot alone. A new position (a stock the fund didn't hold last quarter but does now) is the clearest buying signal, a closed position is the clearest selling signal, and increased or decreased positions describe funds adding to or trimming existing holdings without fully entering or exiting. Aggregating those changes across every filer for a given stock, how many funds opened new positions versus closed them out, gives a market-wide read on institutional positioning that a single fund's filing alone can't.

13F data is always several weeks stale by the time it's public. The 45-day filing window means every filing reflects where a fund stood roughly six to seven weeks earlier, not its current position, which rules it out for any short-term signal. It also discloses long equity positions only. It doesn't show short positions, options, or many derivatives, so a fund's actual net exposure to a stock can look very different from what its 13F alone suggests. And it says nothing about entry price or current conviction. A position reported unchanged for four straight quarters could reflect either strong continued conviction or simple inertia.

Suppose fifteen unrelated institutional managers, none of whom co-invest or share any obvious connection, all report opening new positions in the same mid-cap stock in the same quarter's 13F filings. That kind of convergence, independent analysis arriving at a similar conclusion, is generally read as a meaningfully stronger signal than any single fund's new position alone, even though every filing is already six to seven weeks old by the time it's aggregated this way, and none of it reveals what price those fifteen funds actually paid.