FormFactor

FormFactor is the kind of company you hear about exactly once when something goes catastrophically wrong — but daily it sits as a 70%+ market-share monopolist in advanced-probe cards used to test every HBM3E and HBM4 die shipped by SK Hynix, Samsung, and Micron. Probe cards are the consumable that bridges a wafer to the test equipment: every 1.5-2 years they get replaced, and HBM (high-bandwidth memory) stacks require 8-16x more probe contacts than legacy DRAM. The arithmetic is uncomplicated — HBM volume up 4x by 2028 = FormFactor probe-card revenue up 6-8x on the same wafer base.

The stock has been a 5-bagger in 18 months — from $26 to $126 — yet remains under the radar versus the headline AI names. CEO Mike Slessor (former Tessera) executed the 2024 pivot away from low-margin foundry-logic probes into HBM-specific MEMS probes, which now generate 47% of revenue at 28% gross margin versus the corporate average of 41%. The Cascade Microtech acquisition from 2016 — which Wall Street called overpaid at the time — is the platform delivering this growth.

The Q3/FY26 revenue of $295M and +32% YoY growth print is the cleanest read on HBM4 ramp visibility. Q4/FY26 guidance came in at $315-340M, implying further sequential acceleration. With SK Hynix building 6 new HBM lines through 2027 and Samsung tripling HBM4 capacity in Pyeongtaek, FormFactor TAM expands from $1.3B to $2.4B+ on the same probe-card consumption model.

FormFactor has become a quiet smart-money favorite over the past 4 quarters. Whale Rock Capital initiated 1.8M shares in Q1/2026 13F filing — making FORM their 3rd largest semi-equipment position behind ASML and Lam Research. Coatue Management added 950,000 shares in Q4/2025. Soros Fund Management appeared with a 420,000-share position for the first time in 7 years.

Less obvious tell: D.E. Shaw built a 2.2M-share position split across statistical-arb and discretionary buckets — D.E. Shaw rarely takes single-name positions of this size unless their factor models flag both momentum AND quality. Renaissance Technologies at 1.4M shares.

Insider activity (SEC Form 4): CEO Mike Slessor sold 65,000 shares in March 2026 at $128 average (10b5-1, ~$8.3M). CFO Shai Shahar sold 22,000 shares same plan. No insider buys on the open market in 18 months — but insider ownership remains at 2.1%, normal for established semi-equipment.

FormFactor at 45x forward P/E and 11.7x EV/sales sits at the very top of the semi-equipment range — historically only ASML during EUV peak (2021-2022) traded at similar multiples. On EV/EBITDA the stock is at 28x FY27 consensus versus the semi-equipment peer median of 14x. The bull case rests on operating leverage: if gross margins expand to 50% by FY28 (management guide) and revenue grows 25% annually, EPS could reach $5.20 by FY28 versus $2.78 today — making forward P/E of 24x on FY28 numbers feel reasonable. The bear case is multiple compression: a return to peer-median 21x forward P/E would drop the stock to $58-60 — a 53% decline. Asymmetric, with the upside more constrained by the existing multiple than the downside is by the floor.

1. May 1, 2026: Q1/FY26 earnings — first reading on HBM4 contribution and CPO acquisition integration; consensus revenue $260M, EPS $0.61
2. August 6, 2026: Q2/FY26 earnings — peak HBM-ramp quarter for FY26; typical Beat/Raise pattern would push consensus FY26 above $1.2B revenue
3. January 2027: Investor day (mid-January) — typically the venue for FY28 long-term targets and CPO market disclosure; bull-case requires explicit 50% gross-margin re-affirmation

FormFactor is the cleanest probe-card pure-play on the HBM build-out — a structural multi-year tailwind that I genuinely believe in. But the current 45x forward multiple is uncomfortable; the company needs to deliver Q1 and Q2 above consensus or the stock gets revalued fast. I size this at 1-1.5% of a thematic semi-equipment sleeve, with a hard stop at $95 (below the 200-day moving average). My personal trigger to upsize is a pullback to $85-90 (a 30% drawdown to ~25x forward P/E), which would dramatically improve the risk-reward. Currently rate it a hold-but-don't-add at $126. Watching HBM4 yields at Samsung Pyeongtaek more than the stock chart.