13D vs 13G vs Form 4: SEC Ownership Filings, Deadlines and What They Signal

On October 10, 2023, the SEC adopted the first big overhaul of its beneficial ownership deadlines in decades. Its fact sheet notes that the deadlines for the initial Schedule 13D and 13G had not been updated since 1968 and 1977. The new rules cut the time an activist has to disclose a stake from 10 days to five business days, and require amendments within two. Combined with the two-business-day Form 4 for insiders, that makes these filings the fastest public view of who is building, cutting or controlling a stake in a company. If you are new to ownership filings, start with our guide to 13F filings, the slower quarterly report.

What is the difference between Schedule 13D and Schedule 13G?

Both schedules disclose beneficial ownership of more than 5% of a class of voting equity. The difference is intent: Schedule 13D is for holders who may seek to change or influence control; Schedule 13G is a short form for holders who don’t.

The SEC’s fact sheet puts it plainly: “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.” A 13D is the long form. It requires the filer to describe the source of funds, any contracts or arrangements involving the shares, and, in Item 4, the purpose of the transaction, including plans for mergers, board changes or other major actions. A 13G asks for much less, because the filer has certified it is not trying to influence control.

“Beneficial ownership” is broader than holding shares in your name. It includes voting or investment power exercised through others, and, under the SEC’s 2023 guidance, can involve certain derivatives. The 2023 amendments also clarify that Item 6 of Schedule 13D must disclose interests in all derivative securities that reference the issuer’s equity, including cash-settled ones.

Who can file a 13G instead of a 13D?

Three groups can use Schedule 13G under Rule 13d-1: qualified institutional investors, passive investors under 20%, and exempt investors.

• Qualified institutional investors (QIIs) under Rule 13d-1(b): broker-dealers, banks, insurance companies, registered investment companies and advisers, certain employee benefit plans and certain parent holding companies, holding the shares in the ordinary course of business and not with the purpose or effect of changing or influencing control.
• Passive investors under Rule 13d-1(c): anyone else without control intent who owns less than 20% of the class.
• Exempt investors under Rule 13d-1(d): holders above 5% who are not required to file a 13D because of a statutory exemption or the timing or manner of their acquisition; they file within 45 days after the quarter in which the obligation arose.

The privilege ends when the intent changes. A 13G filer that decides to push for board seats or a sale must switch to a 13D, and that switch is itself a signal worth watching.

What are the 13D and 13G deadlines after the 2023 amendments?

An initial Schedule 13D is due within five business days, with amendments within two business days. Schedule 13G deadlines depend on the filer type, from five business days for passive investors to 45 days after the quarter end for qualified institutions and exempt investors.

The SEC adopted the changes on October 10, 2023 (press release 2023-219). Compliance with the revised 13G deadlines began on September 30, 2024, and structured, machine-readable 13D and 13G data on December 18, 2024. For anyone tracking activists, the practical effect is that a new 13D now appears within about a week of a fund crossing 5%, not up to 10 days.

What is a Form 4, and how fast is it filed?

Form 4 reports a change in holdings by an officer, director or more-than-10% owner, and it is due before the end of the second business day after the trade.

The requirement comes from Section 16(a) of the Exchange Act, which covers every director and officer of a company with registered equity and every beneficial owner of more than 10% of a registered class. The family has three forms, set out in Rule 16a-3:

• Form 3: the initial statement of holdings, within 10 days of becoming an insider.
• Form 4: each purchase, sale, option exercise or other change, within 2 business days.
• Form 5: an annual statement for certain exempt or previously unreported transactions, within 45 days after the company’s fiscal year ends.

The SEC’s 2022 Rule 10b5-1 amendments added two details that matter for anyone reading Form 4s. Filers now tick a box when a transaction was made under a plan intended to satisfy the Rule 10b5-1(c) affirmative defense, and bona fide gifts of securities must be reported on Form 4 rather than waiting for Form 5, according to the SEC’s fact sheet.

How do all the ownership filings compare?

The filings differ on who files, what triggers them, how fast they arrive and how much intent they reveal. A 13D reveals the most intent; a 13F the least.

What do 13D filings and Form 4 insider buying actually signal?

A new 13D signals that a large holder may push for change; a Form 4 open-market purchase signals that an insider chose to add with their own money. Sales say less, because insiders sell for many ordinary reasons.

A 13D is the starting gun of most activist campaigns, the subject of our guide to event-driven strategies. The details are in Item 4: board seats, a sale of the company, a spin-off, capital return. A switch from 13G to 13D by an existing holder is often more telling than a new filer, because it means a passive holder has changed its mind.

For Form 4, look at the transaction code and the 10b5-1 checkbox. A sale under a plan adopted months earlier, under the cooling-off periods set by the 2022 amendments (for officers and directors, the later of 90 days or two business days after the next periodic report, capped at 120 days), tells you little about the insider’s current view. An open-market purchase, especially by several insiders at once, is a deliberate act. Tax-withholding sales on vesting and option exercises are routine and say almost nothing.

How would you read a new 13D, step by step?

Here is an illustrative example with a hypothetical fund and company.

1. The trigger. Fund X crosses 5% of Company Y on Monday. Its Schedule 13D is due within five business days: by the following Monday.
2. The cover page. It reports 6.2% of the class, with shared voting and dispositive power across two affiliated funds.
3. Item 4, purpose. The fund says it believes the shares are undervalued and intends to engage with the board on capital allocation and possibly seek board representation. That is control intent, which is why it is a 13D and not a 13G.
4. Item 5 and Item 6. Item 5 lists trades in the past 60 days with dates and prices, which tells you roughly where the fund built its stake. Item 6 discloses cash-settled swaps adding another 2% of economic exposure.
5. The follow-ups. Two weeks later the fund buys another 1.5%: a material change, so a 13D amendment is due within two business days. If the fund later sells, that too shows up quickly.
6. What to watch. Insider Form 4s at Company Y over the same period: are directors buying alongside the activist, or selling into the rally?

What do these filings mean for executives with concentrated stock?

If you are an officer or director, your trades are public within two business days, and Section 16 adds rules beyond disclosure that shape when and how you sell.

Three rules matter most. Section 16(a) means every sale, purchase, option exercise and, since 2023, every gift appears on Form 4 within two business days, so the market sees your behavior almost immediately. Section 16(b), the short-swing profit rule, lets the company recover any profit from a purchase and sale (or sale and purchase) within less than six months, regardless of intent, which constrains hedging and rebalancing. And your company’s insider trading policy, which sets blackout windows around earnings, decides when you can trade at all. Those windows usually close around the same time the company’s own buyback pauses, a pattern covered in our guide to the buyback blackout period.

The standard answer for diversifying a concentrated position is a 10b5-1 plan: sales are scheduled in advance, after a cooling-off period, and the Form 4 checkbox tells the market they were planned. For downside protection without selling, hedges like a collar need to be checked against your company’s hedging policy and Section 16 first. If you are not an insider but hold a large employer stake, none of these filings apply to you, but the 13Ds and Form 4s of others in your stock are still worth watching.

Where can you find 13D, 13G and Form 4 filings?

All three are on EDGAR, the SEC’s free filing system, searchable by company, filer or form type.

On EDGAR full-text search, enter a company name and filter by form type: SC 13D and SC 13D/A for activist stakes and amendments, SC 13G and SC 13G/A for passive stakes, and 4 for insider trades. Since December 18, 2024, 13D and 13G data are filed in a structured, machine-readable format, which makes screening easier. For a broader view of where these filings sit among other flow data, see our hub on institutional money flow, and for how options activity sometimes front-runs disclosed stakes, see unusual options activity.

What is a checklist for reading ownership filings?

1. Identify the form: 13D (influence), 13G (passive), Form 4 (insider trade), Form 3 or 5 (housekeeping).
2. Check the date of the trigger versus the filing date; the gap tells you how stale the news is.
3. For a 13D, read Item 4 (purpose), Item 5 (recent trades) and Item 6 (derivatives).
4. Watch for a 13G-to-13D switch; it signals a change of intent.
5. For a Form 4, check the transaction code and the 10b5-1 checkbox.
6. Give open-market insider purchases more weight than sales or plan trades.
7. If you are an insider, plan sales through a 10b5-1 plan and check Section 16(b) before any hedge or repurchase.

Frequently asked questions

Key takeaways

1. Crossing 5% of a company’s voting equity triggers a Schedule 13D or 13G.
2. Schedule 13D is for investors who may seek to influence control: due in 5 business days, amendments in 2.
3. Schedule 13G is for passive investors and institutions; qualified institutions can file 45 days after the quarter ends.
4. Officers, directors and 10% owners report trades on Form 4 within 2 business days.
5. Open-market insider purchases usually say more than sales; the 10b5-1 checkbox on Form 4 separates planned sales.
6. For executives, every trade, plan sale and gift is public quickly, and Section 16(b) can claw back short-swing profits.

Sources and method

1. 17 CFR 240.13d-1 (Rule 13d-1) — 5% trigger, Schedule 13D and 13G eligibility and deadlines
2. SEC press release 2023-219 — 2023 beneficial ownership amendments adopted October 10, 2023
3. SEC fact sheet, Modernization of Beneficial Ownership Reporting (Release 33-11253) — old vs new 13D and 13G deadlines, 10 p.m. cut-off, compliance dates
4. 15 U.S.C. 78p (Exchange Act Section 16) — Form 3 within 10 days, Form 4 within 2 business days, short-swing profits
5. 17 CFR 240.16a-3 — Forms 3, 4 and 5; Form 5 within 45 days after fiscal year end
6. 17 CFR 240.13d-2 — 13D amendments within two business days; 13G amendment timing and 10% trigger
7. 17 CFR 240.13d-101 (Schedule 13D) — Items 3 to 6, including trades in the past 60 days
8. SEC fact sheet, Rule 10b5-1 amendments (Release 33-11138) — Form 4 checkbox for 10b5-1 trades, gifts on Form 4, cooling-off periods
9. SEC, EDGAR full-text search — finding 13D, 13G and Form 4 filings

Chart 1 converts rule deadlines into approximate maximum calendar days (business-day deadlines across a weekend; quarter-based deadlines for a trigger on the first day of a quarter); these are Proflex approximations. Chart 2 simplifies Rule 13d-1 and Section 16(a). Chart 3 and the worked example are illustrative. Deadlines are as of October 2026. This page is general information, not legal advice.