Teradyne now owns a piece of the consumable every AI chip is tested through

FormFactor's Form D, filed October 20, dates a completed $300,000,056 equity sale to one investor to October 6, six days before the Teradyne announcement and near the stock's high. The shares have fallen hard since, while insiders at both companies sold.

Richard TangRichard Tang · 2 min read
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Mike Slessor, FormFactor's chief executive
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Mike Slessor, FormFactor's chief executive, has filed a stock sale every month of 2026 through September; the company reports third-quarter results on October 28.

FormFactor's+3.99% — FormFactor, up 3.99 percent today Form D, filed October 20, settles when the loudest endorsement in semiconductor test actually got paid: a completed $300,000,056 sale of common stock to one investor, first sale October 6, six days before the announcement 1. The filing names no buyer; the amount and the lone investor match the stake Teradyne+4.10% — Teradyne, up 4.10 percent today disclosed on October 12 2. On October 6 the stock traded near its 2026 high of about $148 3. It has since closed as low as $105.01 4. Even there, it remained up 88 percent for the year 4.

Test is the bottleneck, and the consumable is the recurring part

AI accelerators are assembled from stacked dies, and a chip built from several dies needs more test steps at tighter tolerances between the tester and the wafer 5. The probe card, the interface that connects a tester to each die, wears out and gets replaced, so this demand recurs with wafer volume rather than with machine cycles 5. FormFactor is the largest probe-card supplier, and its revenue shows the turn: growth has accelerated for three straight quarters, to about 32 percent year over year in the June quarter 6.

FormFactor's growth turned sharply higher as AI test demand built

$150M$200M$250M$300MQ4 '23Q2 '24Q4 '24Q2 '25Q4 '25Q2 '26up 32 percent year over year
Data
Revenue
Q3 '23$171.58M
Q4 '23$168.16M
Q1 '24$168.73M
Q2 '24$197.47M
Q3 '24$207.92M
Q4 '24$189.48M
Q1 '25$171.36M
Q2 '25$195.8M
Q3 '25$202.68M
Q4 '25$215.16M
Q1 '26$226.14M
Q2 '26$258.24M
Quarterly revenue in USD millions from FormFactor's SEC filings; the June 2026 quarter is the latest reported.6

The tester maker now sits inside the interface layer

Teradyne builds the testers those cards plug into, and its chief executive Gregory Smith said the hardest test problems in advanced packaging, silicon photonics and memory cannot be solved by a single company 2. An equity stake moves one of the largest test-equipment makers inside the interface layer its own machines connect through.

For probe-card rivals Technoprobe and Micronics Japan, that pairing is a qualification risk, because jointly developed sockets can exclude them 5. The announcement itself disclosed no joint orders, no exclusivity and no timeline, so the collaboration remains a framework to be qualified over coming quarters 5.

Insiders sat on the other side of the trade

Two days after the announcement, FormFactor chief executive Mike Slessor sold 11,098 shares 7. Over the past year he has sold 169,624 and bought none 7. Company-wide, insiders recorded 32 sales and zero purchases 7. Two Teradyne insiders filed their own sales on October 19 8. At 72 times earnings, the price already assumed execution that a framework has not delivered 9.

The verdicts arrive together: Teradyne reports on October 27, FormFactor on October 28 109. The bottleneck is real and the alignment is the right strategic answer. The buyers of that strategy are Teradyne's shareholders; the sellers of the stock are the people who run both companies.

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