AXT Inc's stock plummeted 5.10% during intraday trading on Thursday, extending its pattern of sharp pullbacks from recent record highs.

The decline occurred despite the broader semiconductor equipment sector trading higher, with Applied Materials, Teradyne, ASML, and Lam Research all posting gains. The stock's underperformance against sector strength highlights pronounced individual selling pressure from short-term profit realization following the stock's surge to all-time highs.

Market concerns have emerged regarding the long-term stability of the company's technology moat, as the evolution of silicon photonics could potentially temper future demand growth for indium phosphide substrates, which are critical base materials for high-speed optical modules used in AI communications.