Teradyne rose 6% on the semiconductor-test bid and the Japanese precision-reducer names that build robot joints rallied with it, while Cognex gave back a strong run.

Teradyne led the basket at +6.1% to $402.74, riding the semiconductor-test-and-automation bid that ran through the whole equipment complex. Test is the chokepoint that gates whether HBM stacks and advanced-logic die ship at all, and Teradyne's exposure to AI-infrastructure test demand made it the cleanest liquid proxy on a day when the sister semicap names — Applied Materials, Lam and KLA — were all firmly green. The move was a sector read, not a company headline: capital leaning back into the tooling that has to scale before any accelerator or humanoid actuator reaches volume.

The more thesis-specific action sat in the robot-joint chokepoint — the precision reducers, servos and bearings that convert motor torque into controlled motion, a supply base still concentrated in Japan. The cohort rallied as a group: Nabtesco's US line +8.4% to $16.79 at the cycloidal-reducer choke, THK +5.5% to $23.58 in linear motion, Schaeffler +3.3% to $8.83, Yaskawa +3.2% to $69.39 in servo drives and industrial robots, and FANUC +2.1% to $20.81. When five separate names across the harmonic-drive, linear-guide and servo layers move up together, the read is a genuine bid on the actuation bottleneck rather than a single stock's noise — the physical constraint that every humanoid roadmap eventually runs into.

The laggard was machine vision. Cognex fell −3.5% to $60.67, but the tape tells a profit-taking story rather than a fundamental one: the stock traded as high as $64.40 intraday before closing near its low, a reversal after a strong run rather than a repudiation of an outlook that management's own Q2 guidance had left intact. Symbotic eased −1.2% to $41.19 at the warehouse-automation layer. The perception-and-vision choke gave back ground on the day even as the actuation choke bid — a rotation within the automation stack.

The calendar builds toward the humanoid narrative. THK reports Q2 on August 31, Tesla's Optimus V3 reveal and Fremont production start are targeted for the summer, and Ambarella and NVIDIA both print August 26 for the edge-compute-and-perception read. Further out, ABB's robotics divestiture to SoftBank is expected to close by late 2026, RoboBusiness runs in Santa Clara October 19–21, and the DFARS ban on Chinese-melted NdFeB and SmCo magnets takes effect January 1, 2027 — the policy date that ties the reducer-and-motor supply chain back to the same rare-earth chokepoint pressuring the drone basket.