GUIDE • START HERE
What Is a 13F Filing?
Four times a year, large US institutional managers have to tell the public which US-listed stocks they own. That disclosure is Form 13F — and understanding its edges matters as much as understanding its contents.
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IN THIS GUIDE
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The one-sentence definition
DEFINITION
Form 13F is a quarterly report, required by Section 13(f) of the Securities Exchange Act of 1934, in which institutional investment managers holding at least $100 million in Section 13(f) securities disclose those holdings to the SEC within 45 days of the end of each calendar quarter.
The rule dates to 1975, when Congress wanted a public window into the growing influence of institutional money on US equity markets. The filings are free, public, and searchable on the SEC’s EDGAR system.
Everything interesting about 13F data follows from three constraints built into that sentence: it covers only a defined list of securities, only long positions, and only as of a date that has already passed.
Who has to file
The obligation attaches to an institutional investment manager that exercises investment discretion over $100 million or more in Section 13(f) securities. The phrase is broader than it sounds. It is not limited to hedge funds.
- —Hedge funds and their management companies
- —Mutual fund and ETF managers
- —Pension funds and endowments
- —Insurance companies
- —Banks and trust departments
- —Family offices
- —Registered investment advisers (RIAs)
- —Corporate venture arms holding public equities
Once triggered, the obligation runs for the rest of that calendar year and continues into the following year’s first three quarters.
THE TWO DETAILS THAT TRIP PEOPLE UP
The test is investment discretion, not ownership — a manager trading someone else’s money still files.
The $100 million threshold counts only Section 13(f) securities, so a firm managing $5 billion in bonds and $40 million in US equities is under the threshold and does not file.
What gets reported
The reporting universe is a specific, published list. The SEC maintains the Official List of Section 13(f) Securities and updates it quarterly. It consists mainly of:
INSIDE THE REPORTING UNIVERSE
- —Equities listed on US exchanges (NYSE, Nasdaq, and others)
- —US-listed put and call options
- —Exchange-traded funds (ETFs)
- —American Depositary Receipts (ADRs)
- —Certain convertible notes
17,500+
entries on the SEC's official Section 13(f) securities list — the exact universe a 13F reports against, refreshed every quarter.
SEC Official List of Section 13(f) Securities
For each position, the manager reports the fields below. We break down each column here.
| Field | What it tells you |
|---|---|
| Issuer name | The company behind the security, as the filer writes it. |
| Security class & CUSIP | Common stock, calls, puts, ADR — and the identifier that makes exact matching possible. |
| Market value | The position marked to the quarter-end price, in dollars. |
| Share or principal amount | The size of the position — the column that reveals real buying when value moves on price alone. |
| Option flag | Whether the line is a put or a call rather than stock. |
| Discretion & voting authority | Who decides on the position, and who votes it — sole, shared, or none. |
What is excluded
This is the half most readers underweight. A 13F is a partial picture by design, and the exclusions are structural rather than accidental.
NEVER APPEARS ON A 13F
- —Short positions. The SEC is explicit that shorts are not reported and must not be netted against a long in the same security.
- —Leverage. There is no field for borrowings, margin, or fund equity. An unlevered book and a four-times-levered book file identically.
- —Foreign-listed equities. A stock trading only on a non-US exchange is not a Section 13(f) security.
- —Bonds, Treasuries, cash, commodities, currencies. A manager with half the book in Treasuries discloses none of it.
- —Private company stakes. Not Section 13(f) securities, so absent no matter how large.
The practical upshot: a 13F tells you what a manager held long in US-listed equities. It does not tell you what the manager was betting on. We work through a recent case where that distinction proved decisive.
The three form types
Searching EDGAR turns up three variants, and mixing them up leads to bad conclusions.
| Form | What it is | What to do |
|---|---|---|
| 13F-HR | Holdings Report. The real thing — the information table with every disclosed position. | This is what you want. |
| 13F-NT | Notice. A near-empty filing saying the manager’s holdings are being reported by a different manager. | It does not mean the firm holds nothing; it means you are looking in the wrong place. |
| 13F-HR/A | Amendment. A restatement or addition to a previously filed holdings report. | Check whether one exists before relying on the original — amendments can materially change the picture. |
Why 13F data is useful — and where it misleads
Used within its range, 13F data is genuinely valuable. It is the only free, standardized, legally mandated window into what large managers hold in US equities, and it goes back decades.
It supports questions like: which names has this manager held across many quarters? Where is the book concentrated by sector? Did share counts actually rise, or did the position just appreciate? Which managers were accumulating a name before it became consensus?
It does not support: copying a portfolio, inferring conviction from position size, gauging risk, or treating a disclosed holding as current.
IF YOU TAKE ONE THING FROM THIS GUIDE
A 13F is a research starting point, not a trade signal. The filing you are reading describes a date that can be more than four months in the past, and the manager has no obligation to tell you what changed since.
Frequently asked questions
What is a 13F filing?
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Who has to file a 13F?
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What securities appear on a 13F?
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What is not reported on a 13F?
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Is a 13F filing public?
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Keep reading
HOW-TO
How to Read a 13F Filing
The information table column by column, and the share-count trick that reveals real buying.
CALENDAR
13F Filing Deadlines 2026
Every quarterly deadline, and how the 45-day rule handles weekends and holidays.
COMPARISON
13F vs 13D vs 13G
Three forms answering three different questions, at three very different speeds.
COMPLIANCE
13F Filing Requirements
Who must file, the $100M test, and 13F-HR vs 13F-NT.