SEC Form 4 reference

SEC Form 4 Transaction Codes

Q: Which Form 4 transaction codes are most common?

In AlphaScala’s sample of 50,023 transaction rows filed Jul 23 – Oct 21, 2026, the most common codes were S (38.4%), M (21.2%), A (20.2%) and F (10.0%). Code P, open market or private purchases, made up 3.3% of rows.

Q: What are Form 4 transaction codes?

One-letter codes that say what kind of transaction each line of a Form 4 reports. General Instruction 8 of the SEC’s Form 4 lists 20 of them and tells filers to enter the code in Table I, Column 3 for non-derivative securities and in Table II, Column 4 for derivative securities.

Q: Which Form 4 code means an insider bought shares?

Code P, "open market or private purchase of non-derivative or derivative security". Grants (A) and exercises (M and X) also add shares, but they are not purchases at a market or negotiated price.

Q: Which Form 4 code means an insider sold shares?

Code S, "open market or private sale of non-derivative or derivative security". Shares withheld for tax (F), gifts (G), dispositions to the company (D) and tenders into a takeover (U) also reduce holdings without being sales in the market.

Q: What do V and K mean on a Form 4?

Neither appears as a transaction code on its own. V goes in a separate column next to the code when a transaction is "voluntarily reported earlier than required". K is added to another code, as in "S/K" or "P/K", when the transaction involves an equity swap or a similar instrument.

Q: When is a Form 4 due?

General Instruction 1(a) says Form 4 "must be filed before the end of the second business day following the day on which a transaction resulting in a change in beneficial ownership has been executed". Some transactions, such as small acquisitions under Rule 16a-6 (code L), may be reported later on Form 5.

Every line of a Form 4 carries a one-letter transaction code that says what kind of transaction it reports. General Instruction 8 of the SEC's Form 4 lists 20 codes in five groups. This page quotes each definition and counts how often each code appears in the Form 4 filings AlphaScala holds.

Of the 50,023 transaction rows AlphaScala holds for Form 4s filed Jul 23 – Oct 21, 2026, open market or private purchases (code P) were 3.3% and sales (code S) 38.4%. Awards, exercises, tax withholding and gifts (codes A, M, F and G) made up 53.1%.

SEC Form 4 filings as of Oct 21, 2026

Definitions: SEC Form 4, General Instruction 8 (Transaction Codes), on sec.gov. Counts: AlphaScala's copy of SEC EDGAR Form 4 filings; see our methodology.

How often each code appears in real Form 4 filings

Filed Jul 23 – Oct 21, 2026

Code	Meaning	Rows	Share of rows	Filings with the code
S	Open market or private sale	19,214	38.4%	7,022 (35.0%)
M	Exempt exercise or conversion	10,617	21.2%	3,389 (16.9%)
A	Grant or award	10,109	20.2%	7,963 (39.6%)
F	Shares withheld for tax or exercise price	4,987	10.0%	3,727 (18.6%)
P	Open market or private purchase	1,647	3.3%	987 (4.9%)
J	Other acquisition or disposition	1,072	2.1%	566 (2.8%)
G	Bona fide gift	865	1.7%	597 (3.0%)
C	Conversion of a derivative	795	1.6%	270 (1.3%)
D	Disposition to the issuer	557	1.1%	335 (1.7%)
X	In-the-money exercise	40	0.08%	16 (0.08%)
E	Short derivative expiration	39	0.08%	8 (0.04%)
L	Small acquisition	38	0.08%	13 (0.06%)
I	Discretionary plan transaction	29	0.06%	26 (0.13%)
W	Will or inheritance	9	0.02%	9 (0.04%)
O	Out-of-the-money exercise	1	<0.01%	1 (<0.01%)
U	Tender in a change of control	1	<0.01%	1 (<0.01%)

Sample: 50,023 transaction rows in 20,089 Form 4 and 4/A filings filed Jul 23 – Oct 21, 2026 by insiders of 2,099 companies with an AlphaScala stock page. One filing can carry several codes, so the filing shares add up to more than 100%. Codes not listed did not appear in the sample.

All 20 codes, as the SEC groups them

General Transaction Codes

P: “Open market or private purchase of non-derivative or derivative security” Code P explained; 1,647 rows, 3.3%
S: “Open market or private sale of non-derivative or derivative security” Code S explained; 19,214 rows, 38.4%
V: “Transaction voluntarily reported earlier than required”; Not in the sample

Rule 16b-3 Transaction Codes

A: “Grant, award or other acquisition pursuant to Rule 16b-3(d)” Code A explained; 10,109 rows, 20.2%
D: “Disposition to the issuer of issuer equity securities pursuant to Rule 16b-3(e)” Code D explained; 557 rows, 1.1%
F: “Payment of exercise price or tax liability by delivering or withholding securities incident to the receipt, exercise or vesting of a security issued in accordance with Rule 16b-3” Code F explained; 4,987 rows, 10.0%
I: “Discretionary transaction in accordance with Rule 16b-3(f) resulting in acquisition or disposition of issuer securities” Code I explained; 29 rows, 0.06%
M: “Exercise or conversion of derivative security exempted pursuant to Rule 16b-3” Code M explained; 10,617 rows, 21.2%

Derivative Securities Codes (Except for transactions exempted pursuant to Rule 16b-3)

C: “Conversion of derivative security” Code C explained; 795 rows, 1.6%
E: “Expiration of short derivative position” Code E explained; 39 rows, 0.08%
H: “Expiration (or cancellation) of long derivative position with value received”; Not in the sample
O: “Exercise of out-of-the-money derivative security”; 1 row, <0.01%
X: “Exercise of in-the-money or at-the-money derivative security” Code X explained; 40 rows, 0.08%

Other Section 16(b) Exempt Transaction and Small Acquisition Codes (except for Rule 16b-3 codes above)

G: “Bona fide gift” Code G explained; 865 rows, 1.7%
L: “Small acquisition under Rule 16a-6” Code L explained; 38 rows, 0.08%
W: “Acquisition or disposition by will or the laws of descent and distribution” Code W explained; 9 rows, 0.02%
Z: “Deposit into or withdrawal from voting trust”; Not in the sample

Other Transaction Codes

J: “Other acquisition or disposition (describe transaction)” Code J explained; 1,072 rows, 2.1%
K: “Transaction in equity swap or instrument with similar characteristics”; Not in the sample
U: “Disposition pursuant to a tender of shares in a change of control transaction”; 1 row, <0.01%

Where the code sits on a Form 4

Form 4 has two tables. Table I reports non-derivative securities, such as common stock, and its Column 3 holds the code. Table II reports derivative securities, such as options and convertible shares, and its Column 4 holds the code. An exercise or conversion is reported in Table II as a disposition of the derivative, with the underlying shares in Table I (General Instruction 4(c)), which is why the exercise and conversion codes show up in both tables.

Two letters on the SEC's list never appear as a code on their own. V goes in a separate column next to the code when a transaction is reported earlier than required, and K is added to another code, as in “S/K” or “P/K”, when an equity swap is involved. Code J is the catch-all: the filer must describe the transaction in the explanation of responses.

Prices are per share and exclude brokerage commissions (General Instruction 5). Holdings after each transaction are reported per line, with shares held directly kept apart from shares held indirectly, for example “By Spouse” or “By X Trust”. Since April 2023 a checkbox at the top of the form shows whether a transaction was made under a Rule 10b5-1 trading plan.

Only codes P and S are purchases and sales in the market or in private transactions. AlphaScala's insider cluster screen and net buying tables count open-market purchases (P) and sales (S) of shares only.

How AlphaScala counts the codes

The sample is every Form 4 and Form 4/A that AlphaScala's daily read of the SEC EDGAR filing index has stored since continuous coverage began on Jul 23, 2026, capped at the last twelve months. It covers filings for companies with an AlphaScala stock page; Form 4s for other issuers are not in it, so the mix describes the listed companies AlphaScala covers rather than every Form 4 filed.

Each row is one line of Table I or Table II, counted as filed: a joint filing or an amendment that repeats a line counts it again. “Filings with the code” counts distinct accession numbers. Median filing lag on the code pages is calendar days from the transaction date to the filing date.

Questions about these codes

Which Form 4 transaction codes are most common?

In AlphaScala’s sample of 50,023 transaction rows filed Jul 23 – Oct 21, 2026, the most common codes were S (38.4%), M (21.2%), A (20.2%) and F (10.0%). Code P, open market or private purchases, made up 3.3% of rows.

What are Form 4 transaction codes?

One-letter codes that say what kind of transaction each line of a Form 4 reports. General Instruction 8 of the SEC’s Form 4 lists 20 of them and tells filers to enter the code in Table I, Column 3 for non-derivative securities and in Table II, Column 4 for derivative securities.

Which Form 4 code means an insider bought shares?

Code P, "open market or private purchase of non-derivative or derivative security". Grants (A) and exercises (M and X) also add shares, but they are not purchases at a market or negotiated price.

Which Form 4 code means an insider sold shares?

Code S, "open market or private sale of non-derivative or derivative security". Shares withheld for tax (F), gifts (G), dispositions to the company (D) and tenders into a takeover (U) also reduce holdings without being sales in the market.

What do V and K mean on a Form 4?

Neither appears as a transaction code on its own. V goes in a separate column next to the code when a transaction is "voluntarily reported earlier than required". K is added to another code, as in "S/K" or "P/K", when the transaction involves an equity swap or a similar instrument.

When is a Form 4 due?

General Instruction 1(a) says Form 4 "must be filed before the end of the second business day following the day on which a transaction resulting in a change in beneficial ownership has been executed". Some transactions, such as small acquisitions under Rule 16a-6 (code L), may be reported later on Form 5.

Insider data on AlphaScala

Insider cluster buys – three or more insiders buying on the open market within 30 days
Market signals – insider, 13F and Alpha Score signals on one board
Stock pages – each company's recent insider purchases and sales
Methodology – data sources and update schedule

Educational reference only, not investment advice. Definitions are quoted from the SEC's Form 4; check the current form on sec.gov before relying on them for a filing. See our risk disclaimer.