Power semis surge 6% on Mizuho's faster Vera Rubin ramp call

Power semiconductor stocks surged Monday after Mizuho flagged a faster NVIDIA Vera Rubin ramp, lifting Wolfspeed 5.74% to $33.61, STMicroelectronics 4.17% to $56.56, and ON Semiconductor 2.96% to $85.11.

"We are the only broad-based U.S. power semiconductor supplier with technologies spanning the full AI power tree," ON Semiconductor CEO Hassane El-Khoury said, as management projected AI data center revenue more than doubling in 2026 and silicon carbide in data center applications growing nearly 60% year over year.

Mizuho's Sunday note told clients to expect strong VR200 NVL72 ramps in 2027, ramping in Q4 2026 led by xAI and Meta, with NVIDIA potentially pushing the four-die transition to Feynman and running VR-Ultra on a two-die configuration. The firm also flagged 2027 CoWoS growth above 75% with NVIDIA and Broadcom, and cloud service provider RPO/backlog at $2.3 trillion, up 3.5x year over year. STMicroelectronics raised its data center ambition to above $1 billion in 2026 and well above $2 billion in 2027, with CEO Jean-Marc Chery citing accelerating adoption of 800 gigabit and 1.6 terabit per second pluggable optics. Wolfspeed reported roughly 30% sequential growth in AI applications in fiscal Q3 and launched its first commercially available 10 kilovolt silicon carbide power MOSFET for high-voltage data center power delivery.

The read-through is direct: Vera Rubin materially raises power management content per rack, so a bigger, on-schedule VR200 ramp means more power semiconductor content shipped across the rack alongside more GPUs. Weeks of chatter about a Vera Rubin delay had weighed on the group; the supply chain check pointing to xAI and Meta anchoring a Q4 2026 ramp removes that overhang. STM is up 110.14% year to date, ON is up 52.65%, and Wolfspeed is up 82.6%, though all three had drifted lower over the past month before Monday's rally.

Content Per Rack Is the Story

ON Semiconductor has been the loudest voice on the power content opportunity. Management said content per rack goes from $15,000 today toward $115,000 under 800V DC architecture — a 7.7x increase. The shift to 800V high-voltage direct current (which reduces transmission losses and allows more power per rack) is central to NVIDIA's next-generation data center designs.

Mizuho's named upside list covers Dell, Credo, NVIDIA, Broadcom and Lumentum, while the three power names benefit indirectly through the read-through. The connection: Vera Rubin materially raises power management content per rack, so a bigger, on-schedule VR200 ramp means more power semiconductor content shipped across the rack, alongside more GPUs.

13F Backdrop Adds Color

Position disclosures filed August 14, covering holdings as of June 30, add background rather than a direct driver. In Wolfspeed, Two Sigma added to 2,272,968 shares valued at $109.7 million, Millennium added to 1,012,371 shares valued at $48.8 million, and Renaissance Technologies opened a new position of 498,900 shares valued at $24.1 million. In ON, Point72 opened a new position of 1,606,182 shares valued at $151.8 million and Balyasny added to 1,517,790 shares valued at $143.5 million. In STM, Situational Awareness disclosed 7,802,700 shares valued at $584.3 million.

These are point-in-time snapshots as of the reporting date and may differ from current positions. Situational Awareness, for example, sold its book as a block trade to Citadel since the latest quarter ended.

The next hard checkpoint is ON Semiconductor's Analyst Day on September 16 in New York, where management is expected to detail the AI power tree strategy. Investors will also parse NVIDIA's next quarterly update for confirmation of the Q4 2026 VR200 ramp trajectory Mizuho described. Any wobble in that schedule would test Monday's rerating in the group.

For investors, the setup is straightforward: power semiconductor content per AI rack is expanding from $15,000 to $115,000 under 800V DC, and the three names here — ON, STM, and WOLF — are the primary listed plays on that transition. STM trades up 110% YTD, ON up 53%, and WOLF up 83%, yet all three had pulled back over the past month before Monday's move. The September 16 Analyst Day and NVIDIA's next earnings call will determine whether the rally has legs or was a one-day repricing.

This article is for informational purposes only and does not constitute investment advice.