Coherent Joins the S&P 500 Soon: Buy the Dip Before the Index Funds Have To?

Coherent (NYSE: COHR) is set to join the S&P 500 on March 23, 2026, creating a date-certain mechanical buying catalyst that has investors watching whether the recent pullback will reverse ahead of the index inclusion date. Inclusion on the index means passive index funds tracking the benchmark must purchase shares regardless of valuation. The stock popped nearly 6% on the announcement but has since pulled back.

Shares hit an all-time high of $300.20 earlier in March but have since retreated 18.5%, driven by sell-the-news sentiment following Nvidia’s $2 billion investment and concerns about geopolitical tensions. However, the stock is still up about 261% year over year.

The Bull Case: Nvidia, AI, and Execution

The fundamental story is compelling. Nvidia committed a $2 billion direct investment in Coherent alongside a multibillion-dollar multiyear purchasing agreement for advanced laser and optical networking products, a strategic validation that goes well beyond a typical customer relationship. The data center segment delivered $1.208 billion in revenue in fiscal Q2, up 34% year-over-year, now representing roughly 72% of total revenue. The data center book-to-bill ratio sits at over 4.0x, signaling demand well ahead of current supply. Coherent has beaten EPS estimates in each of the last four quarters, with an average beat of 6.3%. The quarter delivered $1.29 non-GAAP EPS on $1.685 billion in revenue, with non-GAAP operating margin expanding to 19.9%. CEO Jim Anderson stated: “We expect continued strong growth in the second-half of fiscal 2026 and throughout fiscal 2027 based on strong datacenter and communications demand and our continued production capacity expansion.”

The Valuation Debate

The bear case centers on price. The trailing P/E stands at 244, though the forward P/E compresses sharply to 13 as earnings ramp. Simply Wall St. estimates fair value at $245.70, putting the stock at a 62.9% premium to that model. Director Enrico Digirolomo sold $944,506 in shares on March 6, a notable insider transaction following the stock’s surge. The consensus analyst price target is $276.11, with 15 analysts rating the stock Buy or Strong Buy against five Holds and zero Sells. Jim Cramer called the company “just terrific” and commented positively on its AI infrastructure positioning. Customer concentration risk is real: Coherent’s growth story is tightly coupled to hyperscaler AI capex, and any moderation there flows directly to the top line.

What to Watch

The S&P 500 effective date of March 23 creates a hard deadline for passive fund managers to establish positions. Next earnings are scheduled for May 5, 2026, with Q3 guidance pointing to revenue of $1.70 billion to $1.84 billion and EPS of $1.28 to $1.48. Investors should also monitor the OFC 2026 technology briefing on March 17 in Los Angeles, where CEO Anderson and CTO Dr. Julie Eng are scheduled to present on AI networking and photonics advances.