What Fulgent Genetics, Inc. told the SEC could break it.

Fulgent's largest laboratory customer (aggregating common control) was $70.8M, or 22% of revenue, in both 2025 and 2024, purchased test-by-test with no long-term contract; volume softened in Q4 2025 and is expected to decline in 2026 as that customer begins performing tests internally.

“For the laboratory services segment, aggregating customers that are under common control, one customer comprised $70.8 million or 22% of our revenue in 2025 and $62.6 million or 22% of our revenue in 2024. We began to see lower than anticipated testing volume from our largest customer in the fourth quarter of 2025, and we expect revenues for this customer to decline in 2026 (particularly through the second quarter of 2026) as this customer begins to perform tests internally.”

Fulgent depends on Illumina as the sole supplier of its next-generation sequencers, associated reagents and their maintenance/repair, and on Roche for certain immunohistochemistry equipment, supplies and services; a disruption or inability to replace these sole/limited suppliers would interrupt its laboratory operations.

“we rely on Illumina as the sole supplier of the next generation sequencers and associated reagents we use to perform our genetic tests and as the sole provider of maintenance and repair services for these sequencers; on Roche Holdings AG for certain laboratory equipment, supplies and services for our immunohistochemistry serv”

Fulgent's international business (including increasing genetic-testing sales into China) is subject to U.S. economic/trade sanctions and additional risks from its joint venture in China, which could disrupt customer relationships and derail international expansion.

“In addition, we are exposed to a number of additional risks and challenges related to our joint venture in China.”

If some of Fulgent's tests fall outside LDT criteria and require FDA pre-market review, the FDA could force it to stop selling those tests pending clearance/approval, conduct clinical testing, or restrict labeling — a material threat to its menu and revenue.

“If pre-market review is required for some or all of our tests, should they be determined to fall outside of the LDT criteria, the FDA could require that we stop selling the tests pending clearance or approval and conduct clinical testing prior to making submissions to FDA to obtain pre-market clearance or approval for such IVDs.”