Applied Optoelectronics Plunges 13%, Coherent Drops 9%, Lumentum Falls 8%: Has an Optics Valuation Reckoning Begun?

Shares of optical and photonics suppliers are tumbling at midday Tuesday, with Applied Optoelectronics (NASDAQ:AAOI) stock leading the decline, down 13% to $149. Coherent (NYSE:COHR | COHR Price Prediction) stock is off 9% to $387, while Lumentum (NASDAQ:LITE) stock has slipped 8% to around $825.

The selloff is sharp, but it arrives without a fresh company-specific catalyst from Applied Optoelectronics, Coherent, or Lumentum. The pressure instead traces back to a broad, Korean-led chip and AI rout that is rippling through optical interconnect suppliers tied to data-center buildouts.

For context, the VanEck Semiconductor ETF (NASDAQ:SMH) is down 6% today, and NVIDIA (NASDAQ:NVDA) stock is off 3%. The CBOE Volatility Index or VIX sits at 17.28, which is still inside the normal range. That detail suggests today’s optics drawdown looks more sector-specific than panic-driven.

A Korean-Led Chip and AI Selloff Is the Trigger

The immediate catalyst is a broad-market move, not anything stock-specific to Applied Optoelectronics, Coherent, or Lumentum. A South Korean tech implosion, with SK Hynix overtaking Samsung as Korea’s most valuable company and the KOSPI down 10%, is dragging semiconductors and AI-linked names lower around the globe.

Optical transceiver and laser makers are highly correlated to hyperscaler capex plans, so wobbles in the AI infrastructure trade tend to hit them harder than the average chip name. Lumentum and Coherent both carry heavy datacom exposure, and Applied Optoelectronics has become a near-pure AI optics play as 800G transceiver shipments ramp at its Houston facility.

Recent fundamentals have actually been strong across the group. Coherent’s most recent quarter delivered revenue of $1.8 billion, up 21% year over year, while Lumentum’s most recently reported quarter posted revenue up 90% year over year. Applied Optoelectronics reported revenue of $151 million, up 51% year over year, though that figure missed consensus estimates.

Stretched Multiples After Enormous YTD Runs

Here is where the headline’s question gets interesting. Lumentum’s trailing-12-month P/E ratio is 146x and Coherent’s is 189x. Applied Optoelectronics has no trailing-12-month P/E ratio listed because the company is not currently profitable.

Moreover, the year-to-date (YTD) moves of these stocks have been extraordinary. Applied Optoelectronics stock is up 336% YTD, Lumentum stock is up 126% YTD, and Coherent stock is up 113% YTD. Analyst price targets remain well above current prices, with consensus near $1,111.29 on Lumentum and $384.45 on Coherent.

The bear case is straightforward. At these multiples (or in Applied Optoelectronics’ case, no earnings multiple at all), there’s very little room for disappointment, and momentum-driven names tend to unwind quickly when sentiment shifts. A single bad macro tape can compress multiples faster than the fundamentals can catch up.

However, the bull case is also legitimate. AI data-center demand for 800G and 1.6T interconnects is real, hyperscaler order books look healthy, and rich multiples can reflect rich growth runways when 800G volumes scale. One sharp drawdown inside a broad selloff doesn’t, on its own, confirm a valuation top in Applied Optoelectronics, Coherent, or Lumentum shares.

What Investors Can Watch Next

Investors can watch for whether Applied Optoelectronics, Coherent, and Lumentum shares stabilize near prior breakout levels into the close. A clean bounce could suggest that today’s selling is exhausted, while a weak close would extend the debate over whether the optics trade has gotten too crowded.

The read-through to other AI optics and networking suppliers matters too, since correlated moves often clarify whether sentiment is shifting at the sector level rather than the single-stock level. Forward guidance updates and analyst notes in the wake of today’s action could shape the next share-price moves for Applied Optoelectronics, Coherent, and Lumentum.

For now, the takeaway is that today’s drop is real but not yet a verdict on a full valuation reckoning. Investors holding Applied Optoelectronics, Coherent, or Lumentum shares may want to size their positions carefully given the elevated volatility profile, while those still on the sidelines can use this stretch to study how each company’s fundamentals stack up against multiples that leave little margin for error.