Once a quarter the institutional money on Wall Street is forced to show its hand. Anyone running more than $100 million in US-listed equities has to disclose their long stock holdings to the Securities and Exchange Commission on a filing called Form 13F. The deadline is 45 days after the quarter ends, and once the form is in, it is fully public on EDGAR. That is how the world learns that Berkshire opened a new position in an airline, or that a big pension fund quietly trimmed its mega-cap technology exposure.
TL;DR: Form 13F is the SEC filing that institutional investment managers with at least $100 million in qualifying US equities must file within 45 days of each calendar quarter. It lists their long stock and call-option positions as of the last day of the quarter. It does not show short positions, cash, bonds, foreign-listed stocks, or open-end mutual fund shares. Read with that in mind, it is a useful map of long-only institutional ownership – not a real-time trade ticker.
What a 13F actually is
Form 13F was created by Section 13(f) of the Securities Exchange Act of 1934 – a Congress-mandated transparency rule that took effect in 1978. The SEC’s investor education site states the threshold plainly: any institutional investment manager that “exercises investment discretion over $100 million or more in Section 13(f) securities … must report its holdings quarterly on Form 13F” within 45 days of the end of a calendar quarter (SEC Investor.gov).
“Institutional investment manager” is intentionally broad. It covers registered investment advisers, hedge funds, banks, insurance companies, broker-dealers, pension funds, endowments, family offices and even corporations – as long as the entity has discretion over the qualifying $100 million.
The form itself is called Form 13F-HR (Holdings Report) when the manager keeps the data confidential in-house, or Form 13F-HR/A when amended. There is also a Form 13F-NT (Notice) that a manager files when another manager has already reported the same shares on its behalf – this avoids double counting across affiliated entities.
What is reported – and what is not
The list of reportable instruments is narrower than most people assume. The SEC publishes a Section 13(f) Securities list every quarter that defines exactly what counts. It includes:
- Equity securities of issuers trading on a US exchange (NYSE, Nasdaq, NYSE American).
- Shares of closed-end investment companies and exchange-traded funds.
- Certain equity options and warrants (calls and puts where the underlying is itself a 13(f) security).
- Certain convertible debt securities.
And, importantly, here is what does not appear on a 13F – even at the very largest funds:
| On a 13F? | Examples | Why this matters |
|---|---|---|
| Yes | Apple shares (AAPL), SPY ETF, Berkshire B-shares | Long stock and ETF holdings are fully visible. |
| Yes | Call options on Tesla; puts on QQQ | Long option positions are reported, with a “Put/Call” flag – but the value shown is the option’s market value, not the underlying notional. |
| No | Short equity positions | A 13F is long-only. A fund that is net long $5B and short $4B looks identical on paper to a fund that is just long $5B. |
| No | Cash, Treasury bills, corporate bonds (non-convertible) | Total AUM and dry powder are invisible. |
| No | Open-end mutual fund shares; commodities; FX; private companies | Big chunks of multi-asset and venture portfolios never make the filing. |
| No | Most foreign-listed equities (London-listed Shell, Hong Kong-listed Tencent) | Only securities on the SEC’s quarterly Section 13(f) list – heavily US-listed – are reportable. |
| No | Total-return swaps and most over-the-counter derivatives | Synthetic equity exposure used by some hedge funds and family offices can be material and entirely off-page. |
For each reportable holding, the form shows the issuer name, the class of security, the CUSIP, the market value at quarter-end (in thousands), the number of shares or principal amount, whether it is a share/principal or put/call position, and the manager’s investment discretion and voting authority.
The 45-day calendar – and why it matters
The deadline is 45 calendar days after the calendar quarter ends. That cadence has not changed since the rule took effect. In practice:
That 45-day lag is the single biggest reason a 13F is more useful as research input than as a trade signal. By the time a Q1 filing lands in mid-May, the manager has had six more weeks to add to the position, exit it entirely, or short it back through a different vehicle. A 13F is a snapshot of where the book was, not where it is.
Worked example: how Berkshire’s Q1 2026 filing read
The most-watched 13F on Wall Street belongs to Berkshire Hathaway (CIK 0001067983). Its Q1 2026 13F-HR, filed on May 15, 2026, is a textbook illustration of how to read the form.
That filing – the first 13F under new chief executive Greg Abel – closed 16 positions during the quarter, exited UnitedHealth, Amazon, Visa, Mastercard and Domino’s, opened a new ~$2.65 billion position in Delta Air Lines, started a small stake in Macy’s, more than tripled the Alphabet holding (adding ~$2.6 billion of stock) and continued trimming Chevron.
What the same filing did not tell you: Berkshire’s enormous cash and Treasury-bill pile (reported separately in 10-Q and 10-K filings), any short positions (Berkshire is long-only on the public-equity side but the form would not show them either way), the precise per-share entry prices, and any trades made between April 1 and May 15. The 13F is the holdings as of March 31, not as of the day you read it.
Four common mistakes
- Treating a 13F as a trade signal. The 45-day lag means you are buying after the catalyst, not with it. Academic studies of “13F-following” portfolios generally find any excess return is small and concentrated in a handful of well-identified, low-turnover managers – not the average filer.
- Reading long-only optics as the whole story. A fund showing a $1 billion long Apple position on its 13F may also be running a $1 billion put-spread hedge that is partly reportable and a $500 million total-return swap that is not. Two managers can look identical on paper while running very different net exposures.
- Confusing 13F with 13D/13G. Schedule 13D and 13G are beneficial-ownership filings triggered at 5% ownership of a single issuer, filed within 10 days (13D) or 45 days after year-end (13G). They are about activist intent and concentration, not portfolio reporting. A 13F is a portfolio snapshot; a 13D/G is a single-issuer flag.
- Forgetting that managers can request confidential treatment. The SEC allows confidential treatment of select positions in narrow cases (typically when public disclosure would compromise an ongoing acquisition program). The position is still on file at the SEC, but is redacted from the public version – meaning the public 13F is not always the complete book.
Where to find any manager’s 13F
Every 13F-HR ever filed is free on the SEC’s EDGAR full-text search. The shortcut is to look up the manager’s Central Index Key (CIK) and pull the filing index directly. For Berkshire, that is https://www.sec.gov/cgi-bin/browse-edgar?action=getcompany&CIK=0001067983&type=13F. The information table is a structured XML file you can drop straight into a spreadsheet. Third-party aggregators clean up the data and add change-over-quarter columns, which is convenient but is not the system of record – the EDGAR XML is.
Where this connects
A 13F is one of the cleanest windows into how institutional money is positioned in US stocks, and it is most useful when paired with the rest of the SEC disclosure stack: 10-K, 10-Q and 8-K filings for the underlying companies, the activist signal in 13D/13G filings, and the management-level reads you can get from earnings reports. Tracking ownership concentration also matters for understanding corporate actions like spinoffs and secondary offerings, where institutional support often decides outcomes. Used as part of that toolkit – and not as a stand-alone trade signal – a 13F is one of the best free data sources US investors have.
Sources & further reading
- SEC Investor.gov – Form 13F: Reports Filed by Institutional Investment Managers.
- SEC Division of Investment Management – Frequently Asked Questions About Form 13F.
- SEC EDGAR full-text search – free, primary source for every 13F ever filed.
- SEC Form 13F PDF – the official form and instructions.
- Related on ECMSource: Berkshire’s Q1 2026 13F – worked example, SEC filings explained: 10-K, 10-Q, 8-K, hedge funds explained, how short selling works.
Disclosure: This article was produced with AI assistance and reviewed before publication. It is for informational purposes only and is not investment advice.