Mike Slessor - 13 May 2026 Form 4 Insider Report for FORMFACTOR INC (FORM)

Reporting relationship: CEO, Director
Issuer ticker: FORM
Reported as of: 13 May 2026
Net transaction value: -$1,194,064
SEC form: 4
Accepted by SEC: 14 May 2026, 17:32:14 UTC
Prior SEC filing: 08 May 2026
Next SEC filing: 28 May 2026
Source filing: View source filing
Reporting owner signature: /s/ Stan Finkelstein, Attorney-in-fact for Mike Slessor

Key filing fact

Mike Slessor filed Form 4 for FORMFACTOR INC (FORM) on 14 May 2026.

Key facts

This page summarizes Mike Slessor's Form 4 filing for FORMFACTOR INC (FORM).
12 reported transactions and 0 derivative rows are listed below.
Accepted by SEC: 14 May 2026, 17:32.

Change

Previous filing in this sequence was filed on 08 May 2026.
Current net transaction value: -$1,194,064.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001590177 Primary reporting owner

SLESSOR MIKE

Relationship: CEO, Director
Address: 7005 SOUTHFRONT ROAD, LIVERMORE
Signature: /s/ Stan Finkelstein, Attorney-in-fact for Mike Slessor
Signature date: 14 May 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

FORM transaction

Common Stock

Sale

Transaction value: $85,988
Shares: -700
Change %: -0.15%
Price: $122.84
Shares after: 455,775
Date: 13 May 2026
Ownership: Direct
Footnotes: F1, F2

FORM transaction

Common Stock

Sale

Transaction value: $160,836
Shares: -1,300
Change %: -0.29%
Price: $123.72
Shares after: 454,475
Date: 13 May 2026
Ownership: Direct
Footnotes: F1, F3

FORM transaction

Common Stock

Sale

Transaction value: $372,135
Shares: -2,984
Change %: -0.66%
Price: $124.71
Shares after: 451,491
Date: 13 May 2026
Ownership: Direct
Footnotes: F1, F4

FORM transaction

Common Stock

Sale

Transaction value: $174,305
Shares: -1,388
Change %: -0.31%
Price: $125.58
Shares after: 450,103
Date: 13 May 2026
Ownership: Direct
Footnotes: F1, F5

FORM transaction

Common Stock

Sale

Transaction value: $50,383
Shares: -398
Change %: -0.09%
Price: $126.59
Shares after: 449,705
Date: 13 May 2026
Ownership: Direct
Footnotes: F1, F6

FORM transaction

Common Stock

Sale

Transaction value: $12,747
Shares: -100
Change %: -0.02%
Price: $127.47
Shares after: 449,605
Date: 13 May 2026
Ownership: Direct
Footnotes: F1

FORM transaction

Common Stock

Sale

Transaction value: $89,964
Shares: -700
Change %: -0.16%
Price: $128.52
Shares after: 448,905
Date: 13 May 2026
Ownership: Direct
Footnotes: F1, F7

FORM transaction

Common Stock

Sale

Transaction value: $90,531
Shares: -700
Change %: -0.16%
Price: $129.33
Shares after: 448,205
Date: 13 May 2026
Ownership: Direct
Footnotes: F1, F8

FORM transaction

Common Stock

Sale

Transaction value: $26,114
Shares: -200
Change %: -0.04%
Price: $130.57
Shares after: 448,005
Date: 13 May 2026
Ownership: Direct
Footnotes: F1

FORM transaction

Common Stock

Sale

Transaction value: $26,526
Shares: -200
Change %: -0.04%
Price: $132.63
Shares after: 447,805
Date: 13 May 2026
Ownership: Direct
Footnotes: F1

FORM transaction

Common Stock

Sale

Transaction value: $8,958
Shares: -66
Change %: -0.01%
Price: $135.73
Shares after: 447,739
Date: 13 May 2026
Ownership: Direct
Footnotes: F1

FORM transaction

Common Stock

Sale

Transaction value: $95,577
Shares: -702
Change %: -0.16%
Price: $136.15
Shares after: 447,037
Date: 13 May 2026
Ownership: Direct
Footnotes: F1

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Rule 10b5-1 trading plan

These transactions were reported as open-market trades under a Rule 10b5-1 plan. The plan lets an insider set trading instructions in advance, which can reduce the risk of trading while in possession of material nonpublic information.

Original filing language: transaction made pursuant to a contract, instruction, or written plan intended to satisfy Rule 10b5-1(c).

Explanation of responses 8 footnotes

Footnote F1

The reported sale of shares occurred automatically pursuant to a Rule 10b5-1 trading plan adopted on August 19, 2025.

Footnote F2

Price represents the weighted average sale price for the transaction reported. Price range of shares sold is $122.23 through $123.19. Reporting person undertakes to provide, upon request by the SEC staff or a security holder of the Issuer, full information regarding the number of shares sold at each separate price.

Footnote F3

Price represents the weighted average sale price for the transaction reported. Price range of shares sold is $123.28 through $124.17. Reporting person undertakes to provide, upon request by the SEC staff or a security holder of the Issuer, full information regarding the number of shares sold at each separate price.

Footnote F4

Price represents the weighted average sale price for the transaction reported. Price range of shares sold is $124.22 through $125.20. Reporting person undertakes to provide, upon request by the SEC staff or a security holder of the Issuer, full information regarding the number of shares sold at each separate price.

Footnote F5

Price represents the weighted average sale price for the transaction reported. Price range of shares sold is $125.26 through $126.04. Reporting person undertakes to provide, upon request by the SEC staff or a security holder of the Issuer, full information regarding the number of shares sold at each separate price.

Footnote F6

Price represents the weighted average sale price for the transaction reported. Price range of shares sold is $126.37 through $127.14. Reporting person undertakes to provide, upon request by the SEC staff or a security holder of the Issuer, full information regarding the number of shares sold at each separate price.

Footnote F7

Price represents the weighted average sale price for the transaction reported. Price range of shares sold is $128.37 through $129.07. Reporting person undertakes to provide, upon request by the SEC staff or a security holder of the Issuer, full information regarding the number of shares sold at each separate price.

Footnote F8

Price represents the weighted average sale price for the transaction reported. Price range of shares sold is $129.22 through $129.42. Reporting person undertakes to provide, upon request by the SEC staff or a security holder of the Issuer, full information regarding the number of shares sold at each separate price.