Mike Slessor - 16 Sep 2026 Form 4 Insider Report for FORMFACTOR INC (FORM)

Reporting relationship: CEO, Director
Issuer ticker: FORM
Reported as of: 16 Sep 2026
Net transaction value: -$1,833,817
SEC form: 4
Accepted by SEC: 17 Sep 2026, 19:30:54 UTC
Prior SEC filing: 17 Aug 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 17 Sep 2026.

Key facts

This page summarizes Mike Slessor's Form 4 filing for FORMFACTOR INC (FORM).
3 reported transactions and 0 derivative rows are listed below.
Accepted by SEC: 17 Sep 2026, 19:30.

Change

Previous filing in this sequence was filed on 17 Aug 2026.
Current net transaction value: -$1,833,817.

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: 17 Sep 2026

Reported non-derivative transactions

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

FORM transaction

Common Stock

Sale

Transaction value: $910,920
Shares: -8,737
Change %: -1.8%
Price: $104.26
Shares after: 475,467
Date: 16 Sep 2026
Ownership: Direct
Footnotes: F1, F2

FORM transaction

Common Stock

Sale

Transaction value: $817,098
Shares: -7,773
Change %: -1.6%
Price: $105.12
Shares after: 467,694
Date: 16 Sep 2026
Ownership: Direct
Footnotes: F1, F3

FORM transaction

Common Stock

Sale

Transaction value: $105,800
Shares: -1,000
Change %: -0.21%
Price: $105.80
Shares after: 466,694
Date: 16 Sep 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 3 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 $103.65 through $104.63. 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 $104.66 through $105.615. 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.