Can Lumentum Stock Fall 30%?

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A 30% fall in Lumentum (LITE) stock would not be new. The shares have dropped at least that much within a calendar year in nine of the last ten years. Over those ten years, the median of the stock’s largest fall in each year was 37.3%. The shares lost 19.6% from October 1 to October 30, 2026, while the S&P 500 slipped 1.1%. This time there is also a business risk: new competition for the laser chips Lumentum makes in its own plants. So where is that competition coming from, and what does management say about it?

Where Is Lumentum’s New Competition Coming From?

The competition is coming from China. During Lumentum’s August 11, 2026 earnings call, management was asked about China-based companies coming to market with new indium phosphide fabs. Lumentum relies on the same kind of plants, manufacturing its laser chips at two indium phosphide wafer fabs in Japan.

Management played down the danger. They said some of these Chinese laser suppliers are not delivering in the market today, and their output so far comes nowhere near the big numbers they put out. Management also said Lumentum’s high- and mid-power lasers have very strong differentiation from rivals.

Price is what is at stake. Better factory use, a favorable mix and higher prices on select products lifted Lumentum’s adjusted gross margin in fiscal Q4 2026, management said. They added that Lumentum has been able to raise prices even on some laser chips, because customers get far better yields from them. New Chinese supply could put those price rises at risk.

Components Bring In Two-Thirds Of Lumentum’s Sales

Components, the segment that includes Lumentum’s laser chips, brought in $2.01 billion in fiscal 2026. That makes it the larger of the company’s two segments, at about two-thirds of Lumentum’s $3.01 billion in fiscal 2026 sales. Its sales rose 79.7% from fiscal 2025, up from 35.8% growth the year before.

Investors are paying a high price for that growth. At the October 30 close, Lumentum stock traded at 23.8 times sales, against 3.2 times for the S&P 500. The multiple reached 24.3 at the end of June 2026, the highest of the 40 fiscal quarter ends from fiscal Q1 2017 to fiscal Q4 2026. Lumentum’s price-to-earnings ratio is not meaningful for now, since the company shows a net loss over the latest twelve months. Management said a one-time charge of $7.8 billion on its convertible notes produced the fiscal Q4 2026 loss.

The shares are already off their peak. The October 30 close was 25.8% below the October 6 high of $1,133.40, most of the way to a 30% fall from that high. Even so, at that multiple of sales, the price appears to assume that the components business keeps growing at prices close to today’s.

How Worried Should Lumentum Holders Be?

The threat looks real but slow. For now, Lumentum cannot make enough to meet demand. Management said on the August call that it is still shipping behind customer demand on its EML laser chips. Demand from AI data centers had effectively booked Lumentum’s production capacity through early 2029, the company said, according to news reports on October 9, 2026.

Lumentum has also secured multiple long-term customer agreements, management said in August. While the company is short of capacity, a new Chinese supplier appears to have room to sell without taking Lumentum’s orders. The danger would grow once supply catches up with demand. Separately, Marvell was in advanced talks to buy Lumentum, according to news reports on October 28, 2026. Lumentum shares rose 5.5% that day to $913.95, but closed at $840.70 on October 30, below their $866.18 close before the reports.

Lumentum’s reported gross margin is the number to watch when the company reports fiscal Q1 2027 results, expected in November 2026. The margin stood at 47.4% in fiscal Q4 2026, against 33.3% a year earlier.

How To Act On LITE?

Not necessarily on Lumentum alone, if your goal is long-term wealth. Wealth is built by owning the companies that keep outperforming, the leaders of their industries, wherever they are. Lumentum is one. Over the five years to October 2026, its stock rose 918%, ahead of all 35 other companies in Communications Equipment, where the typical company rose 51%.

Finding companies like these takes comparison across industries and sectors, and that is what the Trefis High Quality (HQ) Portfolio does. It holds 30 quality companies in equal weight and, since its inception in September 2020, has returned more than 105%, ahead of a benchmark that combines the S&P 500, S&P Mid-cap and Russell 2000. See how we find the leaders.

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