13F filings: How to track Berkshire, Bridgewater, and the rest of the smart money
Every quarter, institutional investment managers with discretion over $100 million or more in US equities must publish their long positions to the SEC. That filing is Form 13F. It's how the public knows what Warren Buffett, Bridgewater, BlackRock, and roughly 5,000 other large funds owned at the end of each quarter.
What 13F actually shows
Form 13F lists the manager's long equity positions in 13(f)-eligible securities (US-listed stocks, ETFs, and a few other categories) as of the last day of the quarter. For each holding it shows the security name, CUSIP, share count, and market value.
The filing is due 45 days after quarter-end. So Q1 (Mar 31) 13Fs land around May 15; Q2 (Jun 30) around August 14, and so on.
What 13F does NOT show
13F is long-only. Short positions, derivatives, cash, fixed income, and non-US equities don't appear. A fund that's 50% net long but heavily short hedged looks identical to one that's 95% long with a small cash buffer.
It's also 45 days stale by the time you see it. A manager could have sold a position the day after quarter-end and you wouldn't know until the NEXT quarter's 13F.
And confidential treatment exists: large managers can sometimes request the SEC delay public disclosure of a specific position (typically to avoid front-running while building a position). Berkshire has used this for years on accumulating positions.
How to read fund moves
The most-watched comparisons are quarter-over-quarter changes: new positions, additions, reductions, and exits. A fund opening a $500M new position in a single ticker is a stronger signal than a 5% trim to an existing holding.
Cross-fund consensus is another lens: if 8 of the top 20 value funds independently added the same name in a single quarter, that's harder to explain than a single fund's move.
Be aware of cloning bias: services like Dataroma aggregate 13Fs from 70+ 'superinvestors,' and retail investors often pile into 'new buys' lists. The cleanest signal is the 13F before it's been broadcast — but everyone's reading the same filings, so the edge is in interpretation, not access.
How InsiderWire uses 13F data
We pull Dataroma's aggregated 13F view daily — that's 70+ value-investor portfolios (Berkshire, Pabrai, Klarman, Watsa, etc.) with quarter-over-quarter deltas pre-computed. Each significant addition becomes a Signal tagged source='13f'.
When the same ticker shows up across multiple fund 13Fs in the same window, our consensus engine treats it as a cross-source signal and combines it with any concurrent insider buying or Congressional disclosures on the same name.
Keep reading.
Educational content. Not investment advice. InsiderWire aggregates publicly-available SEC and Congressional filings — past activity is not a guarantee of future returns.