Why optical stocks Lumentum and Coherent were the day’s biggest S&P 500 gainers

Shares of optical-component suppliers Lumentum and Coherent rose to become the biggest gainers on the S&P 500 as investors broadened their search for demand signals within the AI data-center ecosystem. Rather than concentrating solely on chipmakers and other headline names, buyers targeted companies that provide components used deeper in data-center buildouts, lifting the two stocks relative to the wider market.

The move reflected growing caution about the pace of overall spending on AI infrastructure. With fears of a spending slowdown circulating, some market participants are probing further down the supply chain to identify businesses that might still see steady orders even if top-tier chip customers pull back.

That strategy — looking for indications of concrete demand among suppliers of optical links, modules and other connectivity gear — was cited by an industry expert as a reason for the days outperformance by Lumentum and Coherent. Investors see such firms as potential early beneficiaries of sustained data-center upgrades or as more resilient to cyclical softness at the chip level.

The shift in investor focus underscores how granular supply-chain analysis can influence stock performance during periods of economic uncertainty. By seeking companies with direct exposure to data-center deployments rather than upstream semiconductor spending alone, some traders aim to position for pockets of continued growth within the broader AI investment theme.