13D vs 13G vs 13F: Three SEC Filings Every Hedge Fund Watcher Should Know

Executive summary. A Schedule 13D is filed by an investor who acquires more than 5% of a public company with control intent, due 5 business days after crossing the threshold. A Schedule 13G is the passive-investor equivalent for the same 5% trigger, filed mostly by index funds and registered advisers. A Form 13F is a quarterly long-position report from any institutional manager exercising discretion over $100M or more, due 45 days after quarter-end. Three forms, three thresholds, three audiences.

The three filings most often confused on a hedge-fund desk are Schedule 13D, Schedule 13G, and Form 13F. They are governed by three different sections of the same statute, they cover three different reader tasks, and the deadline structure was rewritten as recently as 2024. This is the comparison page. For the full plain-English Schedule 13D primer, see What Is a Schedule 13D Filing; for the full set of 13dwatch research, see /blog/.

The numbers below are pulled from the U.S. Securities and Exchange Commission (SEC) EDGAR full-text search on 2026-04-30 and from the live 13dwatch feed at the same timestamp. Year-to-date 2026 volume: 1,789 initial 13D filings, 11,325 initial 13G filings, 12,793 13F-HR filings. The 13G and 13F lanes carry roughly 6× and 7× the volume of the 13D lane, respectively. If your workflow only watches 13D, you are reading the smallest of the three streams.

What each form actually is

Schedule 13D is the disclosure required by Section 13(d) of the Securities Exchange Act of 1934, added by the Williams Act of 1968. Any person who, after acquiring beneficial ownership, owns more than 5% of a class of voting equity registered under Section 12 must file — if the acquisition carries control intent. The form runs to seven items; Item 4 ("Purpose of Transaction") is where Elliott Management, Starboard, Trian, and Icahn signal a board campaign, a sale, or a leveraged recap. The 13D is the activist's filing.

Schedule 13G covers the same 5% threshold but is filed by investors without control intent. The SEC staff CDI on Sections 13(d) and 13(g) puts it directly: "An investor with control intent files Schedule 13D, while Exempt Investors and investors without a control intent, such as Qualified Institutional Investors and Passive Investors, file Schedule 13G." (SEC, Exchange Act Sections 13(d) and 13(g) and Regulation 13D-G Beneficial Ownership Reporting.) Three filer categories qualify under Rule 13d-1: Qualified Institutional Investors (QIIs), Passive Investors, and Exempt Investors. Vanguard, BlackRock, and State Street file 13G by the thousand.

Form 13F is governed by Section 13(f), added by the 1975 amendments to the Exchange Act. Any institutional investment manager exercising investment discretion over $100 million or more in Section 13(f) securities — exchange-listed equities, certain ETFs, options, certain convertible debt — as of the last trading day of any month in any calendar year must file a quarterly report listing those long positions. The 13F is the institutional position tape: every Berkshire, Pershing Square, Baupost, Tiger Global long disclosure runs through this form. Shorts, cash, foreign securities, and most fixed income are not on it.

The comparison table

The below summarizes the regime as of 2026-04-30. Deadlines reflect the post-2024 rule changes (SEC Press Release 2023-219).

Source for YTD volume: SEC EDGAR full-text search, queried 2026-04-30. Source for deadline structure: SEC Press Release 2023-219, SEC Form 13F FAQ, Investor.gov Schedules 13D and 13G.

What the volume tells you

The form-by-form count is the part most analysts get wrong. The 2026 YTD breakdown (Jan 1 – Apr 30) by month:

Three observations.

13G is six times 13D. The colloquial framing "13D = activist, 13G = passive" understates how dominant the passive side is. For every 13D filed YTD, six 13Gs hit the tape. An analyst who only watches the 13D feed sees a sliver of the beneficial-ownership picture.

13F volume is bimodal. February (6,108) is the Q4 deadline. April (3,283) is the Q3-to-Q4 stragglers plus early Q1 filings. March (325) is empty. A 13F-driven workflow runs in two-month bursts, four times a year.

13G amendments cluster in Q1. February (2,786) and March (2,567) carry the bulk because the post-2024 quarterly cadence forces year-end and Q1 amendments to land in the same window. By April (855), the surge ends.

When each form matters

The reader's task determines which form to read first.

Activist hedge fund analyst. Read Schedule 13D and 13D/A first. The 13D Item 4 disclosure announces the campaign. The amendments cadence (every 2 business days for any material change, post-2024) is now fast enough to track an unfolding board fight in real time. For a sector-and-target map of every 13D filed YTD, see Every 2026 Schedule 13D Filing, Mapped. 13F is corroboration: who else among the elite is long the same name. 13G is mostly noise for this reader.

Allocator or family office. Read 13F first. The quarterly long book of every Berkshire, Pershing Square, Baupost, Appaloosa, Third Point, Duquesne, Viking, Tiger Global, Greenlight, and Lone Pine clears in the SEC EDGAR system 45 days after quarter-end. The follow-on read on which of those managers' 13Fs actually predict subsequent returns is the subject of a separate post: The 10 Hedge Fund Managers Whose 13Fs Actually Predict Returns. 13D and 13G become secondary — they tell you who else is over 5% on a given name once you've identified it via 13F.

RIA or compliance officer. Read 13G to understand which of your concentrated portfolio holdings has crossed an institutional 5% threshold (corporate-action implications, voting blocks). Read 13D to understand activist exposure. 13F is too lagged to matter for client work.

Quant or short-seller. Read 13F filings against the Financial Industry Regulatory Authority (FINRA) short-interest reports to triangulate net exposure. 13F long + FINRA short tells you the squeeze setup. 13D filings against the same names tell you whether the squeeze has a catalyst.

The 2024 deadline reform — what changed

For 56 years, an investor who crossed 5% had 10 calendar days to file a Schedule 13D. That ended on 2024-02-05.

SEC Press Release 2023-219, October 10, 2023, restates the change directly:

"[T]oday's amendments: shorten the deadline for initial Schedule 13D filings from 10 days to five business days and require that Schedule 13D amendments be filed within two business days; generally accelerate the filing deadlines for Schedule 13G beneficial ownership reports..."

Three milestones embedded in that release:

• 2024-02-05. Initial 13D deadline drops from 10 calendar days to 5 business days. Amendments compress from "promptly" to 2 business days.
• 2024-09-30. 13G QII initial deadline shifts from 45 days after year-end to 45 days after quarter-end. Passive Investor 13G drops to 5 business days. 13G amendments compress to 45 days after quarter-end (down from year-end).
• 2024-12-18. Compliance with the new structured-data (XML) requirement for 13D and 13G begins. By 2026, every new beneficial-ownership filing on EDGAR is machine-readable.

Form 13F was not changed. The $100M threshold (set in 1975) remains. The 45-day cadence (set in 1975) remains. A 2020 SEC proposal to lift the threshold to $3.5B was withdrawn after public comment.

The chair at the time, Gary Gensler, framed the 13D change in the same release: "In our fast-paced markets, it shouldn't take 10 days for the public to learn about an attempt to change or influence control of a public company." The 5-business-day compromise was a concession to filers' compliance burden — not an answer to the commenters who wanted T+1.

The honest limits of each form

13D's limit: control intent is self-declared. A filer who acquires 5% can declare passive intent on a 13G, then convert to a 13D when intent changes. Some activists have run the calendar this way. Rule 13d-1's conversion mechanics handle the case, but the SEC does not police intent in real time.

13G's limit: it is a checkbox, not a story. The form asserts passivity; it does not explain it. A 13G from a quant fund and a 13G from Vanguard look identical on tape. Distinguishing them requires the filer's history, not the filing.

13F's limit: long-only, lagged, listable-securities-only. No shorts. Forty-five-day delay. No cash. No foreign securities. No most fixed income. A manager running a 130/30 book reports the 130; the 30 is invisible. By the time the 13F prints, the position is up to 134 days old.

The three forms together — read alongside Form 4 insider transactions and FINRA short-interest data — give a cross-checked picture. None of them, alone, does.

What this means for hedge funds and RIAs

For an emerging hedge fund manager under $500M AUM, the practical takeaway is the workload split.

Watch 13D and 13D/A in real time, daily. The 5-business-day window means stale-data edge has narrowed to roughly 7 calendar days. The 2-business-day amendment cadence means a campaign letter or stake-up disclosure hits the tape inside a single trading week.

Watch 13F quarterly, in two windows: mid-February and mid-May. Q4 13Fs hit by 2026-02-15; Q1 13Fs by 2026-05-15. The other ten months are lower-signal. The trade is not the 13F; the trade is the spread between consecutive 13Fs (additions, exits, sizing changes).

Watch 13G when a name you already own — or are short — appears. A 13G from a QII on a small-cap holding signals concentration risk for an RIA and a possible borrow squeeze for a short-seller. It is not, on its own, a signal to act.

For RIAs and family offices managing concentrated equity positions, the 13G is the form that most often shows up in client meetings ("Vanguard just crossed 5% — what does that mean?"). The honest answer is: it means an index-tracking fund hit 5% via passive flow, and the corporate-action implications (voting concentration, registration-rights triggers) are usually the part that matters, not the trading signal.

A note on what 13dwatch covers — and what it doesn't

13dwatch is a B2B intelligence service that publishes a live, joined feed of activist 13D and 13D/A filings, cross-referenced with Form 4 insider transactions, institutional consensus across the 10 elite portfolio managers we track (Berkshire, Pershing Square, Baupost, Appaloosa, Third Point, Duquesne, Viking, Tiger Global, Greenlight, Lone Pine), and FINRA short-interest. As of 2026-04-30, the public /api/feed returns 13D and 13D/A. 13G ingest and 13F integration are on the roadmap but not yet live.

The numerator we publish is small relative to the EDGAR universe (148 activist filings in the moat as of 2026-04-30T06:44Z) because the value is the cross-source join, not the breadth. The Form 4, 13F, and FINRA layers are what convert a filing into a reading. 13dwatch is not, and will not become, a 13F screener — there are good ones already (WhaleWisdom, Bamsec, Fintel). The 13D/insider/consensus join is the territory the moat covers.

For the 13D and 13D/A feed: see 13dwatch.com or call /api/feed directly (no auth, JSON, 60 most recent).

For the 13G and 13F lanes: read them on EDGAR — SEC EDGAR full-text search is the canonical source.

FAQ

What is the difference between a 13D and a 13G filing?

Both are triggered by crossing the 5% beneficial-ownership threshold of a public company. A Schedule 13D is filed by an investor with control intent; a Schedule 13G is filed by a passive investor or qualified institutional investor (QII) with no control intent. The 13D includes an Item 4 "Purpose of Transaction" disclosure; the 13G does not.

What is the deadline for filing a Schedule 13D in 2026?

5 business days after crossing the 5% threshold, per the SEC's October 2023 amendments effective February 5, 2024. Amendments (Schedule 13D/A) are due within 2 business days of any material change. The old 10-calendar-day deadline no longer applies.

Who has to file a Form 13F?

Any institutional investment manager exercising investment discretion over $100 million or more in Section 13(f) securities — exchange-listed equities, certain ETFs, options, certain convertible debt — as of the last trading day of any month in any calendar year. The threshold has been $100M since the 1975 amendments. Filing is quarterly, due 45 days after quarter-end.

Why do 13G filings outnumber 13D filings six-to-one?

Most beneficial-ownership crossings are passive. Index funds (Vanguard, BlackRock, State Street), registered investment advisers, and bank trust departments file 13G filings every time their indexed flows push them past 5% on a name. Activist 13D filings are concentrated in a small number of filers (Elliott, Starboard, Trian, Icahn, Engaged, Land & Buildings) and a small number of targets per quarter.

Is Form 13F real-time?

No. Form 13F is filed 45 days after quarter-end, which means a position disclosed on May 15 reflects holdings as of March 31. It is the most lagged of the three filings and the worst for short-term trading signal. It is the best for long-term consensus and crowding analysis.

What does Form 13F not include?

Short positions, cash, foreign securities (most ADRs report; most direct foreign holdings do not), most fixed income, most derivatives, and any position covered by a granted confidential treatment request. A 130/30 manager reports the 130 long book; the 30 short book does not appear.

Can a 13G filer convert to a 13D?

Yes. If a 13G filer's intent changes — for example, from passive accumulation to a campaign for a board seat — the filer must file an initial Schedule 13D within 5 business days of the change in intent, per Rule 13d-1. Several activist campaigns have used this conversion. The SEC's staff CDIs on Sections 13(d) and 13(g) cover the mechanics.

Methodology and sources. Form taxonomy and deadlines: SEC Press Release 2023-219, October 10, 2023; Investor.gov, Schedules 13D and 13G; SEC Form 13F FAQ; SEC staff Compliance and Disclosure Interpretations on Sections 13(d) and 13(g). YTD 2026 filing volume: SEC EDGAR full-text search (efts.sec.gov/LATEST/search-index), queried 2026-04-30T06:46Z, date range 2026-01-01 to 2026-04-30, by forms= parameter. Live 13D and 13D/A feed: 13dwatch.com/api/feed, snapshot 2026-04-30T06:43Z, 60 most recent filings (22 SCHEDULE 13D, 38 SCHEDULE 13D/A). 13dwatch moat counts: 13dwatch.com/api/health, 2026-04-30T06:44Z, 148 activist_filings, 928 insider_transactions, 11,181 institutional_holdings, 171,325 short_interest records. This article is research, not investment advice. Long Street Consulting LLC.