QuantumScape (NYSE:QS | QS Price Prediction) stock is surging in Thursday’s midday session, up 11% to $7.67 after the company unveiled a joint research agreement with Honda Motor (NYSE:HMC) to advance solid-state battery technology. The pop builds on an earlier session gain of 8% that accelerated as the news circulated.
Sympathy buying is lifting peer Solid Power (NASDAQ:SLDP) stock, which is trading higher by 4% to around $2.80. Solid Power has no company-specific catalyst today, but renewed enthusiasm for solid-state battery developers is spilling across the group.
The reaction is sharp because it lands inside an otherwise bruising year for QuantumScape shares. QuantumScape stock is down more than 24% year to date in 2026, yet still up more than 81% over the past 12 months, underscoring just how volatile this name has been.
Honda Pact Validates QuantumScape’s Tech
Under the agreement, QuantumScape and Honda will work together under a multi-year plan to develop a solid-state battery and determine the production process, with automotive use cases the obvious target. Importantly, the deal was inked only after Honda completed due diligence on QuantumScape’s QSE-5/QS battery platform, including a hands-on technical study, benchmarking, and stress testing.
That sequencing matters. Honda R&D COO Atsushi Ogawa stated QuantumScape’s technology “demonstrated compelling and unique advantages” during evaluation, and QuantumScape CEO Siva Sivaram called Honda’s review one of the most rigorous assessments of its technology to date. For a pre-revenue developer, validation from a top global automaker is a meaningful trust signal.
The pact also expands QuantumScape’s OEM roster beyond lead partner Volkswagen Group‘s (OTC:VWAGY) PowerCo, where the company has expanded licensing and up to 85 GWh annual production rights.
Solid Power Catches a Sympathy Bid
Solid Power shares are riding the sector tailwind rather than a fresh announcement. The sulfide-electrolyte specialist has its own roster of partners, including BMW, but today’s bid is purely a read-through from the QuantumScape-Honda headline.
The context cuts both ways for Solid Power. The stock is down 34% year to date in 2026, yet still up 42% over the past year. Like QuantumScape, Solid Power remains a low-priced, highly volatile, pre-commercial story where milestones (not earnings) drive the tape.
What Investors Can Watch Next
The bull case is straightforward: a marquee Japanese automaker performed rigorous testing and committed to a multi-year program, which lifts the credibility of the entire solid-state thesis. That’s why Solid Power stock is rallying alongside QuantumScape stock without any news of its own.
The skeptical view deserves equal airtime: both QuantumScape and Solid Power are pre-revenue, cash-burning developers with uncertain commercialization timelines. Insider activity at QuantumScape has also leaned toward disposals in recent weeks, with CTO Timothy Holme and CEO Sivaram among executives reducing positions in May and early June. That’s not a vote of conviction ahead of today’s news.
Near-term, investors can watch for whether QuantumScape stock holds its midday gains into the close, and whether Honda commentary draws follow-on interest from additional OEMs. The next operational checkpoints are QuantumScape’s Eagle Line production scaling and Solid Power’s continuous electrolyte pilot line, which the company is targeting for commissioning by year-end. Position sizing matters here, and investors may want to calibrate their exposure accordingly as these remain speculative names.
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