A 13F filing is a quarterly report that institutional investment managers overseeing at least $100 million in US equities must submit to the Securities and Exchange Commission (SEC). Filed within 45 days of each quarter's end, it discloses the manager's long US stock positions. Because it applies to hedge funds, pension funds, and firms like Berkshire Hathaway, the 13F is the primary public window into what major investors actually hold.
Key Takeaways
- Institutional managers with $100 million or more in Section 13(f) securities must file Form 13F with the SEC every quarter, a threshold set in 1975 and never adjusted for inflation.
- Filings are due within 45 calendar days after each quarter ends, so the Q2 2026 deadline fell on August 14, 2026.
- A 13F shows long positions in US-listed equities only. It does not reveal short positions, cash levels, bonds, or the prices at which trades were made.
- Investors follow 13Fs to track quarter-over-quarter changes in famous portfolios: new positions, big adds, trims, and full exits.
Who has to file a 13F?
Any institutional investment manager that exercises investment discretion over $100 million or more in Section 13(f) securities must file Form 13F, under Rule 13f-1 of the Securities Exchange Act. The threshold is measured on the last trading day of any month during the calendar year, and it applies to hedge funds, mutual fund managers, banks, insurance companies, pension funds, and family offices, whether based inside or outside the US.
The $100 million bar was set when Congress enacted Section 13(f) in 1975 and has never been raised, which is why thousands of managers now file each quarter. Individuals investing purely on their own behalf are generally not required to file, regardless of portfolio size.
When are 13F filings due?
Form 13F is due within 45 calendar days after the end of each calendar quarter: mid-February, mid-May, mid-August, and mid-November, rolling to the next business day when the 45th day lands on a weekend or federal holiday. The Q2 2026 filing, covering positions as of June 30, 2026, was due August 14, 2026.
The SEC does not grant extensions. Filings appear on the SEC's public EDGAR database shortly after acceptance, and many large managers file on or near the deadline itself, which is why 13F season produces a wave of portfolio news in the same few days each quarter.
What does a 13F show, and what does it leave out?
A 13F shows a manager's long positions in Section 13(f) securities, primarily US exchange-listed stocks, ETFs, and certain options, as of the final day of the quarter. It reports the issuer, share count, and fair market value of each holding. Since January 2023, values must be reported to the nearest dollar rather than the nearest thousand.
Just as important is what a 13F does not show:
The 45-day lag matters. A Q2 filing published in mid-August reflects a portfolio that is already six weeks old, the manager may have traded since, and positions opened and closed within the quarter never appear at all.
Why do investors follow 13F filings?
Investors follow 13Fs because they are the only standardized, mandatory disclosure of what the most-watched money managers own. Berkshire Hathaway's filing alone covered a reported $299 billion US equity portfolio as of June 30, 2026, and each quarter's report is scrutinized for what Warren Buffett bought, trimmed, or exited. The same applies to Stanley Druckenmiller's Duquesne Family Office, Bill Ackman's Pershing Square, and ARK Invest.
The signal is in the deltas, not the levels. Quarter-over-quarter comparison reveals three things a single snapshot cannot: brand-new positions (fresh conviction), significant adds or trims (changing conviction), and full exits (abandoned theses). Copying trades blindly is risky given the reporting lag, but 13F data remains one of the best free tools for studying how professional investors position over time.
How do you read a 13F filing?
Start with the quarter-over-quarter changes rather than the raw holdings list: which positions are new, which grew or shrank materially as a percentage of the portfolio, and which disappeared entirely. Raw 13Fs on EDGAR are XML tables with no built-in comparison, so most investors use a tracker that computes the deltas automatically. For example, Berkshire Hathaway's Q2 2026 filing on Backpack's Popular Portfolios shows 29 positions with one added and one removed, per-position quarter-over-quarter changes and portfolio weights for each holding, and an average holding period of 20 quarters.
Three reading habits keep the data honest. First, weight by portfolio percentage, not headlines: a $50 million buy is noise inside a $299 billion book. Second, check turnover: a manager holding positions for 20 quarters on average signals conviction, while high turnover makes any single quarter less meaningful. Third, remember the lag: the filing shows quarter-end, not today.
What to look for in a 13F tracking tool
Reading raw EDGAR filings is free but slow, so most investors use a tracker. Useful evaluation criteria:
- Q/Q change computation. The tool should surface new positions, big adds, and full exits automatically, not just a static holdings table.
- Coverage across managers. Following one filer misses the picture; look for a roster spanning value investors, macro funds, and thematic managers.
- Source integrity. Data should trace back to the actual SEC filings, with the as-of date clearly labeled.
- Context per position. Turnover, average holding period, and portfolio weight turn a list into a readable signal.
- Path to action. If you research a stock a manager holds, being able to view or trade that stock in the same place removes friction.
Common Misconceptions
A 13F is not a real-time portfolio. It is a quarter-end snapshot published up to 45 days later. The manager may have already changed positions.
A 13F is not the manager's whole book. Shorts, cash, bonds, and most non-US holdings are absent. A fund that looks fully long in its 13F may be hedged elsewhere.
A large holding is not a buy recommendation. Managers have different cost bases, time horizons, and hedges. A position that works inside a $299 billion portfolio may not translate to an individual account.
13F is not the same as 13D or 13G. Those forms are filed when an investor crosses 5% ownership of a single company. Form 13F covers the manager's entire US equity portfolio each quarter.
Example: How Backpack's Popular Portfolios turns 13F data into a readable signal
If the criteria above matter to you, this is how Backpack applies them. Popular Portfolios on Backpack tracks 36 institutional portfolios built from SEC 13F filings, including Berkshire Hathaway, Duquesne, ARK Invest, Pershing Square, and Situational Awareness. Each portfolio page shows reported value, quarter-over-quarter change, position count with adds and removals, and turnover with average holding period, so the new positions, big adds, and full exits are visible without opening an XML file. Because Popular Portfolios sits inside Backpack's stocks market, any US-listed stock you find in a manager's filing can be viewed and traded on the same platform.
Explore the full roster at Backpack’s Popular Portfolios.
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