What happened

QuantumScape (QS 3.06%) stock may have rebounded Friday, but that's only after the stock plunged to 52-week lows earlier in the week. The electric vehicle (EV) battery stock was still down 13% through the week as of 2 p.m. ET Friday, according to data provided by S&P Global Market Intelligence. QuantumScape stock is now a whopping 93% off its all-time highs hit in December 2020, just days after the company went public.

The market sell-off had little to do with QuantumScape stock's fall this week. Instead, a C-suite exit sent shockwaves among investors, and many are wondering if Friday's rebound was a reflexive bounce for the stock.

So what

QuantumScape's chief manufacturing officer, Celina Mikolajczak, has left the company.

The development triggered panic-selling in QuantumScape stock, as this isn't just any other executive exit. Mikolajczak, after all, was leading the company from the front to help it progress from development to production stages. She'd joined QuantumScape just about a year ago, and it seemed the company was in real good hands given Mikolajczak's rich experience in the EV battery industry that included stints at EV leader Tesla and battery giant Panasonic.

QuantumScape cited "differing management styles" as the reason behind Mikolajczak's exit.

Now what

With QuantumScape's production head leaving, investors are now worried whether it will be able to meet its goal of starting commercial production of its solid-state batteries by 2025.

So far, QuantumScape's lithium metal solid-state battery technology has garnered a lot of attention. Solid-state technology has strong potential, and QuantumScape's multilayer cells have shown promising lab test results, so much so that four global automakers have shown interest in testing its batteries. QuantumScape has revealed the name of only one: Volkswagen, which has a long-standing partnership and a joint venture with the battery maker.

Yet, for a company that's still years away from production, the exit of a top executive who was in charge of steering the company toward the commercialization of its core product is bound to make investors jittery.

QuantumScape faces high execution risk anyway, and much before it can commercialize its batteries, it must deliver prototypes and samples to automakers as agreed upon and get them validated to convince investors of its product viability. It's a long road ahead and a lot could happen in between, which makes QuantumScape a speculative EV stock at best.