Lumentum is no longer just an “index inclusion trade.” The Nasdaq-100 addition accelerated flows, but the real debate now is whether the company deserves to remain valued as a structural AI infrastructure winner after passive buying fades.

The bullish case is still fundamentally credible:

AI clusters are increasingly bandwidth-constrained, pushing hyperscalers toward optical interconnects and photonics solutions. 

Lumentum’s recent results showed ~90% YoY revenue growth with expanding operating margins, suggesting this is not purely speculative narrative inflation. 

NVIDIA’s strategic investment and partnership materially strengthened the market’s confidence that LITE sits inside the next-generation AI networking stack. 

But the stock is now entering a harder phase:

Index inclusion creates temporary forced buying. Once ETF/passive rebalancing completes, that tailwind disappears. 

Expectations are extremely elevated. Even “good” earnings may no longer be enough, as seen with other AI optics names recently selling off despite solid numbers. 

The sector is becoming crowded. Coherent, Corning, Applied Optoelectronics, and others are all competing for the same AI optical spending narrative. 

My view:

Long-term: still structurally bullish on AI optics

Short-term: likely vulnerable to consolidation after parabolic moves

Best approach: hold core positions if already in profit, but avoid aggressively chasing post-inclusion euphoria

The key question is whether hyperscaler optical spending continues accelerating into 2027. If yes, LITE may evolve into a permanent “AI connectivity platform” valuation tier rather than a cyclical telecom optics company. If AI capex normalises or optical deployment timelines slow, the multiple compression could be brutal because the stock has already rerated massively.