Coherent's AI Optics Party Continues, but Watch for the Hangover

What happened

Coherent Corp. reported strong Q3 results with 21% YoY revenue growth and 55% EPS growth, and guided Q4 revenue growth accelerating to 29%, driven by insatiable AI datacenter demand for optical transceivers. The company’s Datacenter & Communications segment surged 41% YoY, and management’s guidance implies further acceleration, reinforcing the narrative that Coherent is a prime beneficiary of the AI networking buildout. However, beneath the top-line strength, the latest filings reveal concerning working-capital dynamics: inventories ballooned to $2.13B, operating cash flow was only $10M over nine months, and capex remains elevated at $547M. The NVIDIA multi-billion-dollar commitment provides visibility but also increases customer concentration and capacity-related risks, as Coherent must scale indium phosphide production while managing cash conversion. While the market celebrates the 'party,' disciplined investors must weigh whether the company can convert its investment into sustainable free cash flow without margin or liquidity stress.

Implication

The bullish narrative is fully priced at ~$378 with a P/E of 125x and EV/EBITDA of 56x, leaving no room for execution missteps. Investors should resist the temptation to chase the strength and instead await at least two quarters of data showing: (1) Datacenter & Communications growth maintains >25% YoY, (2) inventory growth slows relative to revenue, and (3) gross margins expand or stabilize. The stock's attractive entry point remains near $320, where downside risk is better compensated. Near-term, any guidance disappointment or sign of demand digestion could trigger a sharp re-rating lower, as seen in post-earnings volatility. Until then, the risk/reward is skewed to the downside given the lofty expectations embedded in the stock.

Thesis delta

The thesis shifts from cautiously optimistic on AI optics demand to a more skeptical stance on execution risk. While Q3 results and Q4 guidance confirm strong demand, the cash conversion and inventory build highlight that the company is still in the investment phase, not the harvest phase. Investors should downgrade conviction until concrete evidence of cash generation emerges.