What is a 13F?

What a 13F actually is

A Form 13F is the quarterly disclosure that large institutional investors use to report which US-listed stocks they hold. It exists because of Section 13(f) of the Securities Exchange Act, which Congress added in 1975 to pull institutional holdings into public view. The filer is an institutional investment manager — a hedge fund, bank, insurer, pension, or registered investment adviser — that exercises investment discretion over $100 million or more in “Section 13(f) securities.” Cross that line and you join the several thousand managers who have to show their hand four times a year.

It is the counterpart to the insider-disclosure regime. Where a Form 4 tracks a company’s own officers and directors trading their stock, a 13F tracks the big outside money — the funds and institutions buying and selling that stock from the other side.

Who has to file — the $100 million line

The threshold is $100 million in 13(f) securities, measured on the last trading day of any month in a calendar year. “13(f) securities” means mostly exchange-listed US equities and ETFs, plus certain listed options, convertibles, and warrants — the SEC publishes an Official List of Section 13(f) Securities every quarter that defines exactly what counts.

The number itself is the quiet story. The $100 million floor was set in 1978 and has never been raised for inflation. A 2020 SEC proposal to lift it to $3.5 billion — which would have cut the filer population by roughly 90% — was withdrawn after heavy pushback. Because the threshold is frozen, what looked like a giant institution in 1978 is a mid-size adviser today, and the number of managers required to file keeps climbing year after year.

What’s in a 13F — and what’s missing

A 13F-HR lists every 13(f) security a manager held at quarter-end: the issuer name, CUSIP, share or principal amount, market value, and voting authority. What it leaves out matters as much as what it shows.

Reported on a 13F	Not on a 13F
Long positions in US-listed stocks and ETFs	Short positions
Certain listed options and convertibles	Cash and money-market holdings
Voting authority over those positions	Most non-US-listed and private holdings
	Small positions below the de-minimis floor (under 10,000 shares and $200,000)

So a 13F is a long-only, US-equity-only picture. A fund that hedges heavily, runs net short, or invests mostly overseas can file a 13F that looks almost bare while managing billions. Read one as a partial view of the book, never the whole thing.

The 45-day lag — how to read a stale snapshot

A 13F is due within 45 days of the quarter’s end. Holdings as of March 31 don’t surface until mid-May; the December 31 picture lands in mid-February. By then the manager may have doubled the position or exited it completely.

That lag is the single most important thing to internalize. A 13F captures one day, published up to a month and a half later — and for a position opened early in the quarter, the public sees it as much as four and a half months after the first share was bought. Treat the filing as evidence of what a manager owned, not what it owns now. It is far more useful for spotting themes and gauging conviction across a portfolio than for trading any individual name off the back of it.

13F-HR, 13F-NT, and confidential positions

Most filings are 13F-HR — the holdings report carrying the actual positions. A 13F-NT is a notice: a manager files it to say its holdings are reported on someone else’s 13F, the way a parent firm files one combined report covering its subsidiaries. A 13F-HR/A is an amendment or restatement.

On top of that, a manager can request confidential treatment to delay disclosing a position it is still accumulating, so the market doesn’t front-run the trade. The SEC reviews these requests, and the holding eventually becomes public — but it means a stock’s absence from a current 13F is not proof a manager doesn’t hold it.

How investors use 13Fs — and where they go wrong

13F data powers what the market calls “whale watching”: tracking what Berkshire Hathaway, the big multi-strategy funds, and famous managers bought and sold last quarter. Done well, it’s a genuine source of ideas and a read on where institutional conviction is concentrating. Done badly, it’s performance-chasing on six-week-old data that ignores every caveat above.

The signal lives in the aggregate and the change — a new position taken up across several respected managers at once, or a high-conviction stake that keeps growing quarter over quarter — far more than in any single line item. For the ownership stakes that outside investors must flag once they cross 5% of a company, rather than the quarterly portfolio sweep, see Schedule 13D vs 13G.

Where to track 13Fs

A single 13F is a spreadsheet of hundreds of positions, and its meaning is in how it changed since last quarter and how it lines up against what other managers are doing — exactly the comparison that disappears when thousands of 13F-HRs land inside the same 45-day window. Every one is public and free on SEC EDGAR the moment it files; pulling the institutional-positioning signal out of that wave, across the major indices, is the work Gunpowder’s index-intelligence digests take off your desk.