So, here's what happened with First Solar (FSLR) on Tuesday: the company reported its fourth-quarter numbers, and investors didn't like what they saw. The stock took a nosedive in extended trading.

The headline miss was on the bottom line. First Solar reported quarterly earnings of $4.84 per share. That's not a bad number in a vacuum, but Wall Street was expecting $5.14. So, it's a miss.

Now, the top line was a different story. The company posted quarterly sales of $1.68 billion. That actually beat the Street's estimate of $1.56 billion and was up from $1.51 billion in the same period last year. The company said the increase was driven by selling more solar modules. For the full year 2025, net sales hit $5.2 billion, up from $4.2 billion the prior year, thanks to a 24% increase in third-party module volume.

CEO Mark Widmar put a positive spin on the year, highlighting the company's expansion. "Our growth journey continued into 2025, with the commissioning of our new Louisiana factory and our decision to establish a new facility in South Carolina," he said. He also emphasized the company's strategy in a tricky market: "As we navigated a rapidly evolving environment, we maintained a disciplined approach to contracting and remained anchored in our core principle of pricing and delivery certainty, a key differentiator that our customers value."

But the real kicker for the stock was likely the look ahead. For the upcoming fiscal year 2026, First Solar sees revenue landing in a range of $4.9 billion to $5.2 billion. Analysts, however, were looking for something much bigger—around $6.12 billion. That's a significant gap between the company's guidance and what the market was hoping for.

The reaction was swift. According to market data, First Solar stock dropped 10.91% to $216.67 in Tuesday's extended trading. When you miss on earnings and then guide revenue well below expectations, that's the kind of reception you tend to get.