Two of the companies whose machines must sign off on a stack of high-bandwidth memory before it can be sold into an artificial-intelligence server told investors this month that their order books have never been fuller. Then, in the four sessions after 17 August, their shareholders lost more than the entire month's gains.

This is the rung of the memory supply chain nobody names: process control. Every 2.5D package and every stack of high-bandwidth memory (HBM) has to be inspected, measured and electrically probed before it ships, and the intensity of that work rises faster than wafer volume as stacks get taller. Micron has said its HBM capacity is fully booked through 2026, with meaningful new capacity arriving only in 2027, and HBM4 sells for roughly ten times conventional DDR5 memory per gigabyte — so the test burden is being pulled forward onto lines that already exist rather than deferred to new fabs.

Onto raised the number, then handed back the rally

Onto Innovation, a Wilmington, Massachusetts maker of defect-inspection, optical-metrology and packaging-lithography tools, reported June-quarter revenue of $343m, up 35.3% from a year earlier. That is a sharp break from the 9.5% growth of the prior quarter and the 13.5% decline of a year ago. Advanced packaging and specialty devices — 2.5D logic, HBM and silicon photonics — hit an all-time high at close to half of the quarter, about $170m. Gross margin recovered to 53.4%, from 46.4% two quarters earlier, and operating profit nearly doubled on a third more revenue.

Management then raised full-year advanced-packaging growth to about 80%, from about 50%, and disclosed backlog above $1.1bn. Between 30% and 40% of that backlog delivers in 2027. The shares gapped 14.7% higher the next session. All of it is gone. The competitive claim underneath is real: Onto has been taking inspection and metrology share from KLA and is qualified at TSMC, Samsung and Intel for gate-all-around transistor metrology.

Camtek's paradox

Camtek, an Israeli inspection specialist in Migdal HaEmek with 709 employees, is the awkward case. June-quarter revenue of $133.2m grew only 8.0%, and GAAP operating income fell 14.8% year on year — a second consecutive decline — with operating margin compressing to 20.4% from 25.9%.

Against that, the disclosure: more than $600m of orders year to date, 80% of it advanced packaging, over half from outsourced assembly houses and more than 20% from HBM manufacturers, delivering through 2026 and into 2027. Advanced packaging was 75% of the quarter and is guided to 80% by the fourth. Third-quarter revenue is guided to $158-160m, about 20% above the second. Chief executive Rafi Amit attributed the demand to the industry's transition to HBM4 and continuing 2.5D and 3D packaging capacity. The gap between an order book and a profit-and-loss statement is a delivery schedule — but for two quarters now, the schedule has been costing Camtek margin.

FormFactor is the third leg and the cleanest. Its probe cards are consumed per die tested, and DRAM probe-card revenue rose 48.9% to a record $85m, with HBM about two-thirds of it and two customers already adopting its full-wafer contactor for testing above 10 gigabits per second. Gross margin widened 13.5 points in a year to 50.7%. The one genuine slip is its hyperscaler custom-chip revenue, now expected from 2027.

What actually broke

From 17 to 21 August, Onto fell 18.2%, Camtek 18.4% and FormFactor 19.9%. Over the identical four sessions ASML fell 7.2%, Applied Materials 9.0% and Lam Research 10.5%. Before 17 August all three smaller names were up over the trailing month. The 30-year Treasury yield topped 5.33% on 18 August, a 19-year high, and earnings sitting in 2027 order books discount harder than earnings arriving next quarter.

The rest is an industry argument. Applied Materials reported a record quarter of $9.115bn and guided above consensus, and fell almost 6%, because it declined to lift full-year equipment-market growth beyond 30% while its customers' own capital plans imply nearer 40%. Equipment shares kept falling on 19 August after yields retreated. The market is pricing the gap between what chipmakers say they will spend and what toolmakers will underwrite.

Where the price sits

On price per dollar of trailing gross profit — the fairer lens here, since one-off losses distort Camtek's trailing earnings to 183x — FormFactor is at 21.0x, against 28.2x three months ago and 23.7x six months ago, while its trailing gross profit grew 80% over the same six months. Camtek is at 26.4x against 29.9x in May, though two quarters of falling operating income mean part of that de-rating is earned. Onto is the weakest case for dislocation: 25.3x now, 26.0x in May, but 21.4x in February, having peaked near 30.9x on 17 August. Its forward price/earnings ratio of 36.2x against a trailing 109.5x is the measure of the growth being underwritten — consensus revenue of $1.43bn for the year to January 2027, up 42%.

All three remain among the market's largest twelve-month winners: FormFactor up 299%, Onto 172%, Camtek 77%. What happened last week did not reverse that; it removed August.

The setup

Where it stands — Order books at Onto and Camtek are at records, but four sessions of duration repricing took roughly a fifth off all three names. Would confirm — Camtek delivering third-quarter revenue of $158-160m with operating margin recovering toward its 30-32% year-end target. Would invalidate — Onto's second-half revenue failing to exceed the first half by the guided 25%, or backlog falling below $1.1bn. Watch next — Third-quarter results in late October; FormFactor guided to $270m, plus or minus $10m. Valuation — Price per dollar of trailing gross profit: FormFactor 21.0x, Onto 25.3x, Camtek 26.4x, against roughly 34x for all three in early May.