Why Lumentum’s stock led the S&P 500 higher on Monday

Lumentum led the S&P 500 higher on Monday as optical stocks staged a broader comeback. The move followed Anthropic's IPO filing, which drew fresh attention to the infrastructure underpinning artificial intelligence, alongside other positive developments for the sector.

Lumentum's position as an optical component supplier makes it a useful bellwether for sentiment toward AI-related hardware. Optical components support the high-speed data transmission that large-scale AI computing depends on, so the company's share price can reflect investor expectations for data-center and networking demand. When the stock leads a broad index, it often signals that investors are revisiting parts of the AI supply chain beyond the most prominent chip names.

For observers, the key question is whether this represents a durable shift in sentiment or a short-lived reaction to headline news. Watch whether the gains hold across the optical group in coming sessions, and whether the Anthropic filing translates into concrete signals about infrastructure spending. Because one session's move can reflect positioning as much as fundamentals, sustained confirmation—rather than a single day's rally—is the more meaningful indicator of where the sector is heading.