Why Monolithic Power Systems Stock Is Plummeting Today

By Keith Noonan | October 31, 2025, 3:27 PM

Key Points

Monolithic Power Systems (NASDAQ: MPWR) stock is suffering big sell-offs in Friday's trading. The company's share price was down 11.3% as of 3 p.m. ET and had been down as much as 13.9% earlier in trading.

Monolithic reported its third-quarter results after yesterday's market close and delivered numbers that beat Wall Street's expectations. While the Q3 results beat the market's targets, the company's forward guidance fell short of what some investors were looking for.

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Monolithic stock is sinking despite strong Q3 performance

In Q3, Monolithic generated non-GAAP (adjusted) earnings per share of $4.73 -- beating the average analyst estimate of per-share earnings of $0.10. Revenue for the period came in at $737.18 million and beat the average analyst estimate by roughly $18.9 million. Sales were up roughly 11% year over year in the quarter, and adjusted earnings rose approximately 16.5%. On the other hand, the company's adjusted gross margin declined from 55.8% in last year's quarter to 55.5% in this year's period

What's next for Monolithic Power Systems?

Monolithic is guiding for sales to be between $730 million and $750 million in the current quarter. Meanwhile, the business's adjusted gross margin is projected to be between 55.2% and 55.8%. The company's guidance for Q4 actually looks pretty strong, but some investors seem to have been expecting an even better forecast.

Monolithic's management also indicated that sales connected to enterprise data center customers could increase between 30% and 40% in 2026. With the company posting strong Q3 results and solid guidance, and showing momentum in artificial intelligence (AI), today's sell-off could be a buying opportunity for risk-tolerant investors.

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Keith Noonan has no position in any of the stocks mentioned. The Motley Fool recommends Monolithic Power Systems. The Motley Fool has a disclosure policy.

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