Schedule 13D and Schedule 13G
Both are filed after crossing five percent of a class. Which one is filed is the entire message: one signals intent to influence, the other signals passivity.
MadStockAlerts Research · Updated August 28, 2026
What to take away
- Crossing five percent of a class triggers a filing obligation.
- Schedule 13D is the activist form and must state the purpose of the acquisition.
- Schedule 13G is the passive form, available to qualifying holders on a lighter schedule.
- A holder converting from 13G to 13D is a deliberate change of posture.
- Item 4 of a 13D is the most directly informative paragraph in routine disclosure.
MAD Academy Training Video · 0:45
One Letter Tells You the Intent
Crossing five percent triggers a filing, and whether it is a 13D or a 13G says whether the holder plans to interfere.
This lesson is part of a Stock Alerts + Tools plan.
The trigger
Acquiring beneficial ownership of more than five percent of a registered class of equity requires disclosure. Beneficial ownership includes shares over which the holder has voting or dispositive power, which is broader than outright ownership.
The threshold is per class, which matters where a company has a dual-class share class structure: five percent of the public class can be a very small share of total voting power.
- 1Crossing 5% of a classBeneficial ownership, which includes some derivatives
- 2Intent to influence?
- 3Yes: Schedule 13DWithin ten days, and Item 4 has to say what is wanted
- 4No: Schedule 13GA short form on a periodic schedule. Index funds live here
The two forms
| Schedule 13D | Schedule 13G | |
|---|---|---|
| Filed by | Anyone not eligible for 13G | Passive investors and qualified institutions |
| Signals | An intention to influence control | No such intention |
| Purpose disclosure | Item 4 must state the purpose | Not required |
| Timing | Promptly after crossing the threshold | On a periodic schedule |
| Amendments | Promptly on any material change | Generally periodic |
The choice of form is a legal representation rather than a preference. A holder who intends to influence control and files the passive form has made a false statement, which is why the form filed is genuinely informative.
Item 4 is the document
Item 4 of a 13D states the purpose of the transaction, and it is where an activist sets out what they intend: board representation, a strategic review, a sale of the company, a change in capital allocation. It is written carefully and it is the most directly informative paragraph in the whole filing.
It is also written to preserve optionality. Language reserving the right to acquire more shares, engage with management, or take such other actions as the reporting person deems appropriate is standard, and its absence is more notable than its presence.
The conversion
A holder who filed a Schedule 13G and later files a Schedule 13D has changed posture from passive to engaged. That is a deliberate act with legal consequences and it is not done casually. The conversion is frequently more informative than the original filing was.
The reverse also happens: an activist who settles with a board may convert back to 13G, which discloses that the engagement has concluded, usually on terms set out in a separate agreement filed as an exhibit to an 8-K.
Amendments, and what changes require one
The initial filing is a snapshot. What makes the schedules useful is the amendment obligation, which is far stricter for 13D than for 13G and is the reason an activist position can be tracked in near real time while a passive one cannot.
| Schedule 13D | Schedule 13G | |
|---|---|---|
| Initial deadline | Within days of crossing 5 percent | On a periodic schedule after quarter or year end |
| Amendment trigger | Any material change, including a 1 percent move in ownership | Annually, or on crossing certain thresholds |
| Amendment deadline | Promptly, interpreted as within a day or two | On the periodic schedule |
| What must be stated | Purpose, plans and proposals, in Item 4 | Only that the holding is passive |
The 1 percent amendment trigger on 13D is what makes the filings a running record. A holder building or reducing a position must report each material step, so the sequence of amendments describes the trajectory rather than a single point.
A conversion from 13G to 13D is among the highest-signal events in the disclosure regime. It is a formal statement that a holder who previously described their intent as passive no longer does, and Item 4 has to say what changed.
Groups, and what counts as beneficial ownership
The five percent threshold is measured on beneficial ownership, which is broader than shares held outright, and it applies to a group as though the group were one person. Both definitions catch arrangements that do not look like ownership.
- Shares over which a person has voting power or investment power count, whether or not they own them economically.
- Options, warrants and convertibles exercisable within sixty days count as though already exercised.
- Two or more persons acting together toward a common purpose form a group, and the group's combined holdings are what is measured.
- Certain derivatives conveying economic exposure without voting rights have been the subject of extended dispute and enforcement.
The group provision is what makes activist campaigns reportable. Several holders coordinating cross the threshold together even where none of them does individually, and the failure to file on that basis is among the more commonly litigated points in the regime.
Item 4 of a 13D is the substantive disclosure. It must state the purpose of the acquisition and any plans regarding the issuer, including changes to the board, the capital structure or a sale of the company, and it is written by counsel who expect it to be read closely.