A maker of the machines that stress-test semiconductors before they ship, Aehr Test Systems builds wafer-level (FOX) and package-level (Sonoma, Tahoe, Echo) test and burn-in systems. Its tools screen chips at high voltage and temperature to weed out early failures, serving AI processors, electric-vehicle power chips, and data-center optics. Founded in 1977 by Rhea Posedel in Fremont, California, the company holds over a hundred patents on its WaferPak and DiePak designs.
10-K · Fiscal year ended May 29, 2026 · SEC filing ↗
Backlog rose to $80.6M from $15.2M as FY2026 revenue fell 15% to $50.0M
rebuilt to $80.6M, the highest in years, after two years of depletion. fell 15% to $50.0M and contracted 5.3 points to 35.3% as EV contactor demand stayed soft, while cash rose to $116.4M from $97.1M in equity offerings. The company enters fiscal 2027 with orders booked but sales still declining.
Key takeaways
increased to $80.6M as of May 29, 2026 from $15.2M a year earlier, driven by confirmed purchase orders scheduled to ship within 12 months, reversing the decline to $7.3M in FY2024.
decreased 15.2% to $50.0M, with wafer-level contactor revenue down $19.9M on continued EV demand softness partially offset by a $10.4M rise in wafer-level burn-in systems from silicon photonics customers.
contracted 5.3 points to 35.3% on higher assembly, warranty, freight, and tariff costs alongside lower volume.
Section summaries
Business
Aehr Test Systems provides wafer-level and package-level semiconductor test and burn-in solutions for reliability-critical markets including AI, EVs, and silicon photonics.
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The company operates through two main product lines: full-wafer contact test and systems (FOX family) and package-level test and burn-in systems (Sonoma, Tahoe, Echo).
Wafer-level product net revenues were $31.5 million (63% of total) in fiscal 2026, down from $39.2 million in fiscal 2025, while package-level revenues grew to $18.5 million (37% of total) from $1.6 million in fiscal 2024.
Net loss widened to $7.1M from $3.9M, with the prior year's smaller loss following a $20.7M non-cash income tax benefit that did not recur.
Cash and equivalents rose to $116.4M from $24.5M on $97.1M net proceeds from at-the-market stock offerings, with no reported.
Package-level revenues grew to $18.5M (37% of total) from $1.6M in FY2024 after the Incal acquisition, while customer concentration stayed high at 70% of net revenues from the top five.
What changed
rebuilt to $80.6M from the $7.3M FY2024 low and $15.2M prior-year level, settling the prior filings' watch on whether orders would replenish — they did, on AI, silicon photonics, and GaN demand rather than EV.
fell 15% to $50.0M, extending the decline from FY2025's $59.0M and confirming EV softness persisted beyond the Q3 FY2025 AI/GaN rebound that earlier filings watched for sustainability.
Package-level share reached 37% of FY2026 sales, up from 34% in FY2025 and 2% before the Incal acquisition, tracking the prior watch on Incal's continuing contribution.
specifics were not reported, leaving the on valuation from FY2024 and FY2025 unresolved despite the FY2026 variance charge absence.
Customer concentration eased to 70% top-five from 77% in FY2025 but remains extreme, with three customers at 26%, 14%, and 11%.
What to watch
Q1 FY2027 against the $18.8M Q4 FY2026 base to see if the $80.6M converts to shipments or EV softness persists
Next disclosure to confirm the $80.6M level holds or cancels as orders ship within the 12-month window
Package-level burn-in share in the next quarter to track Incal's contribution after it reached 37% of FY2026 sales
Any figure after the unresolved on valuation and FY2026 margin pressure
Key end markets include AI processors, silicon carbide and gallium nitride power semiconductors for electric vehicles, silicon photonics for data centers, and high-bandwidth memory (HBM).
Customer concentration is high, with the top five customers accounting for 70% of fiscal 2026 net revenues and three individual customers representing 26%, 14%, and 11% respectively.
increased sharply to $80.6 million as of May 29, 2026, compared to $15.2 million a year earlier, driven by confirmed purchase orders scheduled for shipment within 12 months.
The company holds 125 active patents globally and relies on proprietary software, trade secrets, and its patented WaferPak Contactor and DiePak Carrier designs to compete.
Customer concentration, large-deal lumpiness, and competitive/technological pressures are the dominant risks, with new emphasis on AI and tariff-related uncertainties.
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Sales to the five largest customers were 70% of in fiscal 2026, with three customers individually at 26%, 14%, and 11%, making the business highly vulnerable to any single customer loss or pullback.
A substantial portion of comes from a small number of high-value system sales, and orders can be canceled or rescheduled with limited penalties, creating significant quarter-to-quarter volatility.
The FOX and Sonoma product families face intense competition and require lengthy customer qualification; failure to gain broader market acceptance would materially harm future results.
Newly emphasized risks include the impact of global tariff policy changes and trade disputes on costs and demand, as well as competitive, legal, and operational risks from the company's increasing use of AI.
Reliance on sole-source and limited suppliers for critical components exposes the company to supply disruptions, cost increases, and potential intellectual property leakage.
Aehr operates principal facilities in Fremont, CA, with additional leased offices in Germany and the Philippines.
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The main Fremont, CA facility spans 51,289 sq ft under a lease renewed in Dec 2022, expiring Sep 2030, with a five-year extension option the company now expects to exercise.
A small 492 sq ft sales and support office is leased in Utting, Germany, with an automatic annual renewal mechanism.
A 6,458 sq ft facility is leased in the Clark Freeport Zone, Philippines, under a lease amended in 2023 that expires Jun 2029 with a three- or five-year renewal option.
Following the Incal acquisition, the company vacated an inherited Fremont office in May 2025 and terminated that lease in Nov 2025 to consolidate California operations.
Management believes existing Fremont facilities are adequate for current and foreseeable needs, while regularly evaluating global capacity.
From time to time, we are subject to various claims and legal proceedings that arise in the ordinary course of business. We accrue for losses related to litigation when a potential loss is probable and the loss can be reasonably estimated. For additional information regarding le…
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From time to time, we are subject to various claims and legal proceedings that arise in the ordinary course of business. We accrue for losses related to litigation when a potential loss is probable and the loss can be reasonably estimated. For additional information regarding legal proceedings, refer to Note 9 – Commitments and Contingencies in the Notes to Consolidated Financial Statements.
Aehr Test Systems' FY2026 revenue fell 15% to $50M, resulting in a net loss of $7.1M, while cash surged to $116.4M from equity offerings.
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declined to $50.0 million in FY2026 from $59.0 million in FY2025, driven by a sharp drop in contactor sales.
The company reported a net loss of $7.1 million, compared to a net loss of $3.9 million in the prior year, as contracted.
Cash and cash equivalents increased dramatically to $116.4 million, primarily due to $97.1 million in net proceeds from public stock offerings.
The independent auditor identified valuation for excess or obsolete inventory as a critical audit matter due to significant management judgment in forecasting demand.
The company acquired Incal Technology in July 2024 for $22.2 million, adding $10.7 million in and $12.0 million in .
A change in the company's fiscal year-end from late May to late June was approved, effective for fiscal year 2027.