Sometimes the market gives you a report card, and sometimes it gives you a detention slip. For SES AI Corp. (SES), Wednesday's after-hours session felt more like the latter.

The battery materials company saw its shares crumble after releasing fourth-quarter results that missed revenue expectations and came with a fiscal 2026 outlook that left analysts wanting more. The stock dropped 10.53% to $1.53 in extended trading.

Here's what went wrong: SES AI reported quarterly revenue of $4.56 million. That's not just a miss—it's a 31.33% shortfall from the $6.64 million analysts were expecting. The good news? The company lost less money than predicted, posting a loss of four cents per share versus the expected five-cent loss.

But investors are forward-looking creatures, and what they saw ahead didn't impress them. SES AI guided to fiscal 2026 revenue in the range of $30 million to $35 million. The Street was expecting about $51.67 million. That's a gap wide enough to drive a battery-powered truck through.

CEO Qichao Hu tried to put a positive spin on things, saying the company will "continue to focus on our capex-light business model to grow revenue in ESS, drones and materials." He also highlighted the company's AI platform, noting that "its high-quality scientific data and intuition are becoming a valuable asset to the exciting development in AI4Science."

Translation: We're trying to do more with less, and our AI is getting smarter about discovering new materials. But for now, the numbers tell a story of slower growth than Wall Street had penciled in.

It's one of those classic market moments where beating on earnings but missing on revenue—especially with weak guidance—gets you a one-way ticket to the penalty box. The question now is whether SES AI's "capex-light" approach pays off in the long run, or if investors will remain skeptical until they see those revenue numbers start climbing toward expectations.