Applied Optoelectronics (AAOI) shares tumbled 5.04% during Monday's intraday trading session, giving back earlier gains as investors reacted to the company's aggressive capacity expansion plans and regulatory concerns. The stock had initially extended its post-earnings rally in pre-market and early trading, but sentiment quickly soured amid worries about potential oversupply in the optical components market.

The decline was triggered by AAOI's announcement during its recent earnings call that it plans to expand production capacity by more than tenfold over the next two years. While the company reported strong Q2 results with record revenue and robust demand for its 800G and 1.6T products, the massive capacity expansion raised concerns about future margin pressure and an oversupply scenario. Analysts noted that the sell-off reflects a correction in supply expectations rather than a collapse in demand, as the willingness to significantly expand capacity itself indicates strong industry sentiment.

Adding to the negative pressure, market rumors that the FCC intends to restrict imports of Chinese data center components further weighed on the optical networking sector. The broader group of optical stocks also declined, with Coherent, Lumentum, and Ciena among the notable losers, as the combination of supply concerns and regulatory uncertainty prompted a sharp pullback in AAOI shares.