How do you read a Schedule 13D filing?
A Schedule 13D is the report a person or group files with the SEC after acquiring more than 5% of a voting class of a listed company's shares (Investor.gov). Since the SEC's October 2023 amendments, it is due within 5 business days (Dechert, 2023). Read the cover page, Item 4 and Item 5 first.
What is the difference between Schedule 13D and 13G?
Both report ownership above 5%; the form depends on intent and on who the holder is. Schedule 13D is the long form, used by anyone who may seek to change or influence control of the company. Schedule 13G is a shorter statement open to qualified institutional investors such as registered advisers, banks, broker-dealers and insurers, and to certain passive and exempt investors (Investor.gov).
A switch from 13G to 13D is itself a signal. It usually means a holder that described itself as passive now wants a say in how the company is run.
What are the 13D and 13G deadlines?
The SEC shortened the deadlines in its October 2023 amendments to Regulation 13D-G. Law firm summaries of the final rule agree on the main dates:
| Filer | Initial filing | Amendments |
|---|---|---|
| Schedule 13D | 5 business days after crossing 5% (was 10 calendar days) | 2 business days after a material change; a 1% change is deemed material |
| Schedule 13G, passive investor | 5 business days after crossing 5% | 2 business days after crossing 10% or a 5% change; otherwise 45 days after the quarter of a material change |
| Schedule 13G, qualified institutional investor | 45 days after the end of the quarter in which it crossed 5% | 5 business days after the end of the month of a 10% crossing or 5% change; otherwise 45 days after the quarter |
Sources: Shearman, 2023; Dechert, 2023; Wyrick, 2023; Katten, 2023. Older SEC pages still show the previous deadlines, so check the date of any guidance you read.
Step 1. Read the cover page
The cover page names the issuer, the class of shares and its CUSIP, and each reporting person. For each one it gives the shares held with sole and shared voting power, sole and shared dispositive power, and the percent of the class. Note every reporting person: activist funds often file together with their general partner, their manager and the individual who controls them.
Step 2. Read Item 4, purpose of the transaction
Item 4 is the reason to read a 13D. The filer states why it bought the shares and any plans relating to the matters listed in subparagraphs (a) through (j), which include mergers, asset sales, board changes and changes to the company's capital or dividend policy. Many filers state that no reporting person has a present plan on those matters except as disclosed, as in a 2026 filing on Allot (SEC EDGAR).
Read past the boilerplate. Phrases about engaging with the board on strategy, nominating directors or exploring a sale are where an activist campaign first becomes public. Compare each amendment's Item 4 with the last one; a new sentence there often comes before a letter or a proxy fight.
Step 3. Read Item 5 and the transaction list
Item 5 gives the holding and the percent of the class, and lists trades in the shares during the past 60 days, often in a table with dates, amounts and prices (SEC EDGAR, 2026 filing on TransAct). The pattern tells you whether the holder built the stake slowly or bought quickly before filing.
Step 4. Check Items 3, 6 and 7
Item 3 shows the source of the money, including any margin loans. Item 6 lists contracts and arrangements, such as cash-settled swaps, options or cooperation agreements with other holders. Item 7 lists exhibits: a letter to the board, a joint filing agreement or a settlement agreement is often attached here and says more than the form itself.
How do you find new 13D filings?
Search the company in SEC EDGAR and filter the form type to SCHEDULE 13D, or SC 13D for older filings, and their amendments. EDGAR full-text search finds 13D filings that mention a phrase such as "nominate" or "strategic alternatives" across all companies, and our guide to free SEC filing search tools covers alerts. For the full set of ownership records on one company, see how to find who owns a company.
Where does Tamarly Intelligence help?
Tamarly Intelligence is Tamarly's research platform on companies, funds, countries and markets, built from official filings and open data. Company pages show institutional holders from 13F filings, and a deals database is built from SEC merger filings, so you can follow a campaign from a stake to a transaction. Every figure links to the filing it came from. Tamarly shows no market prices. Pair 13D with quarterly holdings, explained in how to read a 13F filing.
See institutional holders and merger filings on company pages, free for 7 days
Frequently asked questions
How long does an investor have to file a Schedule 13D?
5 business days after crossing 5% of a voting class, under the SEC's October 2023 amendments, down from 10 calendar days (Wyrick, 2023). Amendments are due within 2 business days of a material change.
Does a 13D mean an activist is involved?
Not always. Any holder above 5% that is not eligible for Schedule 13G, or that may seek to influence control, files a 13D. Read Item 4: an investment-only purpose with standard language reads very differently from plans to seek board seats or a sale.
Who can file the shorter Schedule 13G?
Qualified institutional investors, such as registered investment advisers, investment companies, insurers, broker-dealers and banks, plus certain passive and exempt investors (Investor.gov). A 13G filer that later seeks to influence control must switch to a 13D.
About the author. Melvine Manchau is the founder of Tamarly and author of the Tamarly Newsletter. He previously worked at PwC, Salesforce, BlackRock/eFront and Lazard.
About Tamarly Research. Tamarly Research is part of Tamarly Media, which holds no investment positions. Tamarly is a New York research house that studies how AI is changing regulated institutions.