Who files a 13F
The filing obligation sits with the manager, not the fund. An "institutional investment manager" is any entity that exercises investment discretion over other people's money: investment advisers, hedge fund and mutual fund managers, banks, broker-dealers, insurance companies and pension plans. Foreign managers can be covered too. A person investing only their own account is not a manager and does not file.
The test is $100 million in Section 13(f) securities, measured at fair market value on the last trading day of any month. Meeting it once is enough to trigger a year of filings. According to the SEC's Form 13F FAQ, a manager that crosses $100 million in any month of a calendar year must file for the December quarter of that year and for the March, June and September quarters of the next year, even if its holdings later fall back below the line.
Because the manager files, one 13F usually aggregates every account it runs. A firm with three funds and a set of separate accounts reports one combined list, not one per fund. Where two related managers share discretion over the same holdings, one may list them and the other may file only a notice pointing to it.
What counts as a 13(f) security
Not every holding is reportable. The SEC publishes an Official List of Section 13(f) Securities each quarter, and only securities on that list go on the form. The list is mostly:
- Stocks that trade on a US exchange, including US-listed shares of foreign companies
- Shares of closed-end funds and exchange-traded funds
- Certain convertible debt, equity options and warrants that appear on the list
Shares of open-end mutual funds are not reportable. Shares of foreign companies that trade only outside the US are not reportable either. Cash, private company stakes and most bonds are not 13(f) securities.
Each holding appears in the information table with the issuer name, the class of security, the CUSIP, the market value at quarter end, the number of shares, the type of investment discretion and voting authority. Since January 3, 2023, values are reported to the nearest dollar rather than in thousands.
What a 13F shows and what it leaves out
| Question | Does the 13F answer it? | Notes |
|---|---|---|
| Which US-listed stocks did the manager hold long at quarter end? | Yes | Only securities on the Official List |
| How many shares and what market value? | Yes | Value at quarter end, to the nearest dollar since 2023 |
| Did the position grow or shrink since last quarter? | Partly | Compare two filings; trades within the quarter are invisible |
| Held call or put options? | Partly | Listed options it holds may be reported; written options are not |
| Short positions? | No | Not reported and not netted against longs |
| What price the manager paid or when it bought? | No | No cost basis, no trade dates |
| Why the manager owns it? | No | No statement of intent, unlike a 13D |
| Foreign-only shares, bonds, cash, private stakes? | No | Outside the Official List |
| Very small positions? | Not always | Positions under 10,000 shares and under $200,000 may be left out |
Two more gaps matter. First, a manager can ask the SEC for confidential treatment of a position, for example while it is still building a stake or holding a risk arbitrage position, and if the request is granted the holding is left off the public filing for a period. Second, option rows describe the underlying stock, so the share count and value shown generally refer to the underlying shares, not the premium the manager paid. A call option position can therefore look much larger than the money actually at risk.
13F deadlines
Every report is due 45 days after the calendar quarter ends. When the 45th day lands on a weekend or federal holiday, the deadline moves to the next business day. The SEC grants no extensions. The SEC's FAQ lists these dates:
- Quarter ended March 31, 2026: due May 15, 2026
- Quarter ended June 30, 2026: due August 14, 2026
- Quarter ended September 30, 2026: due November 16, 2026
- Quarter ended December 31, 2026: due February 16, 2027
Many managers file close to the deadline, so the bulk of a quarter's 13Fs arrives in the last few days of the window. By the time you read the newest one, the holdings it describes are at least six weeks old, and often more.
How to read a 13F
You can read any 13F for free on EDGAR. Our guide to searching SEC EDGAR filings covers the search itself. Look up the manager by name and filter the filing list by form type:
- 13F-HR is the holdings report. Most filers use it. A "combination report" is also filed as 13F-HR and lists some holdings while pointing to another manager for the rest.
- 13F-NT is a notice. It lists no holdings and names the other manager that reports them.
- 13F-HR/A and 13F-NT/A are amendments. A restatement replaces the whole earlier filing; a new-holdings amendment adds only the entries that were left out.
Inside a 13F-HR there is a cover page, a summary page with the number of holdings and the total value, and the information table. Read the summary page first. Then sort the table by value and compare it with the previous quarter's filing. The useful questions are simple: which positions are new, which were sold out entirely, which changed size meaningfully, and how concentrated the top ten holdings are.
A worked example
The figures below are illustrative. Harrow Lane Capital and the companies named are hypothetical.
Harrow Lane Capital files a 13F-HR for the quarter ended June 30. Its information table shows 1,200,000 shares of Company A (ticker QRVX) worth $18,000,000, implying a quarter-end price of $15.00. Its prior filing, for March 31, showed 400,000 shares. It also shows call options on 500,000 shares of Company B with a listed value of $10,000,000, and no position in Company C, which it held the quarter before.
The filing arrives on August 14. By then Harrow Lane has had six more weeks to trade. A reader who treats the Company A row as a fresh signal is reacting to a decision the manager made as long as four and a half months earlier.
What the filing does support is a factual statement: at June 30, Harrow Lane owned 1.2 million Company A shares, up from 400,000. If Company A has 40 million shares outstanding, that is 3% of the company, under the 5% line where a Schedule 13D or 13G would be required. That ownership fact is worth knowing before a shareholder vote or a takeover offer, which is how 13F data is most useful in special situations work.
How investors use 13F data
The best uses treat a 13F as ownership research, not a trade list.
- If you are studying a company before a vote or a deal, add up the 13F holders to see who owns the shares that will decide it, and which of them are index funds, active managers or event-driven funds.
- If you want to know whether an activist has a wider portfolio, read its 13F for context, then rely on its 13D for the stake and the intent.
- If you are checking whether a stock is crowded, compare the number of active holders and their position sizes across several quarters rather than one.
- If you are following a manager you respect, read its letters and its 13D filings alongside the 13F, because the 13F alone cannot tell you the reasoning or the hedges.
For insiders rather than funds, Form 4 filings arrive within two business days and say far more about timing and price. Any 13F reading should also go on your catalyst calendar with its quarter-end date, so the age of the data stays visible.
Where this goes wrong
Treating stale holdings as current. A 13F is a snapshot of a past date filed weeks later. The position may have been sold before you read it.
Missing the hedge. Short positions and written options are not reported. A long stake that looks like a high-conviction bet may be one leg of a pair trade or an arbitrage position.
Reading option values as dollars at risk. Option rows generally describe the underlying shares. A large listed value can correspond to a small premium.
Assuming a missing stock was sold. A holding can drop off because of the de minimis test, confidential treatment, a change in which affiliated manager reports it, or because the security left the Official List.
Copying a manager's portfolio. You see the end result of their decisions without their entry prices, sizing rules, exits or reasons. Most 13F holdings of large managers also include index and client-mandated positions that reflect no view at all.
Trusting aggregator data without checking. Third-party sites parse 13Fs into tables, and parsing errors happen, especially around amendments and combination reports. The difference between primary and secondary sources applies here: confirm any figure you rely on in the filing itself on EDGAR. Our roundup of stock research tools for individual investors covers which tools parse filings and which only display them.
Dombey's published research uses ownership filings as one input among several when it writes up a catalyst; see the research archive.
The bottom line
A 13F tells you which long positions in US-listed securities a large manager held on the last day of a quarter, and nothing about why, when or at what price. It arrives up to 45 days late and leaves out shorts, written options, foreign-only shares, cash and small positions. That makes it a good map of who owns a stock and a poor guide to what anyone is doing now. Read it as ownership research, compare quarters, and confirm anything important in faster filings such as a 13D, Form 4 or 8-K.