Whale Watching: Hedge Funds & Public Filings

What big investors disclose and how to use it.

1. What Hedge Funds Do — Hedge funds are private investment pools that can bet on prices rising or falling, use leverage and trade almost anything. Here are the main strategies, how they charge and what their filings can and cannot tell you.
2. Reading 13F Filings — Form 13F shows the U.S. stock holdings of large investment managers at the end of each quarter. Here is who files, what the form includes and leaves out, and how to read one.
3. Form 4 Insider Trades — When company executives, directors and big owners buy or sell their own company’s stock, they must report it within two business days. Here is how to read Form 4 and why insider buying tells you more than selling.
4. Congressional Trade Disclosures — Members of Congress must disclose their stock trades, and many investors track them. Here is how the disclosure rules work, why the data is delayed and fuzzy, and where the debate over banning member trading stands in 2026.
5. Filing Delays & Survivorship Bias — Copying famous investors looks easy in hindsight. Filing delays mean you buy late, and survivorship bias means you only hear about the winners. Here is how both distort the picture.
6. Turning Filings into Ideas — Filings work best as a source of research ideas. Here is how to filter them for the strongest clues, from concentrated new positions to insider buying clusters, and how to check an idea before acting.
7. Building Your Own Process — Watching whales is most useful as one part of a repeatable research routine. Here is a simple weekly and quarterly process for using public filings, tracking results and learning from them.