Applied Optoelectronics' stock plummeted 5.63% in pre-market trading on Monday, reflecting significant downward pressure on the shares.

The decline follows the company's reported first-quarter earnings per share of -$0.12, which missed market expectations, placing sustained pressure on the stock since mid-May. Additionally, the market views the company's announced $600 million at-the-market equity financing plan as a short-term overhang suppressing share price recovery.

Broader weakness in the optical communication equipment sector also contributed to the sell-off, with sector peers like Lumentum and Ciena trading lower. While the company recently received production approval for 800G optical transceiver capacity at its Xinbei factory, this positive catalyst was overwhelmed by the confluence of negative factors driving the stock lower.