What is a 13F Filing? Definition, Formula, and Example
A 13F filing is a quarterly SEC report disclosing the long U.S. equity holdings of any institutional investment manager with at least $100 million in qualifying assets under management.
What Is a 13F Filing?
A 13F is a quarterly report filed with the U.S. Securities and Exchange Commission by every institutional investment manager that exercises discretion over $100 million or more in qualifying U.S. equity securities. Required under Section 13(f) of the Securities Exchange Act of 1934, the filing discloses long equity positions—stocks, ADRs, ETFs, convertible bonds, and call/put options—as of the last day of each calendar quarter. Filings are due within 45 days of quarter-end and are publicly searchable through SEC EDGAR.
How a 13F Is Structured
Filing thresholds and contents:
- AUM threshold: $100 million in 13(f) securities (the SEC publishes the official 13(f) list quarterly)
- Reporting deadline: 45 calendar days after each quarter-end (Q1 due May 15, Q2 due August 14, Q3 due November 14, Q4 due February 14)
- Disclosed: long stock, ADRs, ETFs, closed-end funds, convertible bonds, long call options, long put options (reported as derivatives with notional values), and certain shares of registered investment companies
- Not disclosed: short positions, cash, sovereign and corporate bonds, foreign securities not listed on U.S. exchanges, commodities, currencies, swaps, and private equity stakes
For each holding the manager reports CUSIP, issuer name, share count, market value as of quarter-end, and investment discretion (sole, shared, or none). Confidential treatment can be requested for material positions still being accumulated, but the SEC routinely denies these requests for liquid names.
Worked Example: Reading Berkshire's 13F
Berkshire Hathaway's Q4 2024 13F (filed February 14, 2025) listed 38 positions. Top reported holdings included:
- AAPL: 300.0M shares, market value ~$75.1B (down from 905M shares pre-2024 trim)
- BAC: 680.2M shares, market value ~$30.0B
- AXP: 151.6M shares, market value ~$45.0B
- KO: 400M shares, market value ~$24.9B
A reader compares two consecutive 13Fs to derive trading activity. AAPL share count fell from 400M (Q3 2024) to 300M (Q4 2024) → 100M shares sold. The dollar value is reconstructed using the volume-weighted average price during the quarter (≈$220 → ~$22B sold). Brand-new positions appear with no prior-quarter line; eliminated positions disappear entirely.
Aggregator services such as Whalewisdom, HedgeFollow, and Dataroma scrape EDGAR and republish change tables sortable by Buy / Sell / New / Exit, with concentration and tenure metrics layered on top.
When Traders Use 13F Filings
- Tracking superinvestors (Berkshire, Pershing Square, Scion, Greenlight, Third Point) for thesis ideas
- Detecting hedge-fund crowding in single names—a high "13F holder count" can become a forced-selling target during a drawdown
- Identifying activist accumulation before a public 13D filing crosses the 5% threshold
- Sector-rotation analysis: aggregating 13F changes across hundreds of managers to read institutional allocation shifts
- Building hedge-fund replication portfolios that mimic specific managers
Limitations and Common Misconceptions
The 45-day delay is the central caveat. By the time a 13F is public, the position may already be exited, doubled, or hedged with derivatives that do not appear on the form. Short positions and credit-default swaps are entirely absent—a fund showing a long stock line may be net short via puts, swaps, or single-stock futures.
Cost basis is not reported. The market-value column is the quarter-end mark, not the entry price. Performance derivation from 13Fs alone is imprecise. Form 13F covers only U.S.-listed qualifying securities, so international funds disclose only their U.S. equity book; their overall exposure is invisible. Many quantitative funds, market-makers, and prop firms file 13Fs that bear almost no resemblance to their actual risk, because their U.S. long-equity book is a hedging artifact rather than a directional bet. Retail copy-traders who mimic 13Fs blindly produce lagged, lossy replications of strategies whose dynamic risk management never appears on the filing.