Aehr Test Systems vs. C3.ai: Which Technology Stock Is a Better Buy in 2026?

Aehr Test Systems (NASDAQ:AEHR) and C3.ai (NYSE:AI) both aim to capitalize on the artificial intelligence boom, but they operate on opposite ends of the technological spectrum. Which is the better buy?

Aehr focuses on the hardware side, providing essential testing equipment for chips used in high-growth markets like electric vehicles and data centers. C3.ai provides the software layer, helping massive organizations deploy predictive artificial intelligence applications. Both companies are navigating a shifting landscape where rapid innovation meets lumpy revenue cycles.

The case for Aehr Test Systems

Aehr Test Systems designs and sells specialized equipment used to test chips at the wafer level to identify defects before they reach final assembly. The company is a niche player among semiconductor stocks, providing essential testing equipment for silicon carbide chips. Customer concentration like this adds a layer of risk to the business, as its five largest customers accounted for roughly 70% of net revenues in fiscal 2026.

In FY 2026, revenue reached close to $50.0 million, representing a decline of approximately 15.2% compared to the previous year. This revenue drop contributed to a net loss of roughly $7.1 million for the period. The net margin, which shows how much of each dollar earned becomes profit after all expenses, was nearly -14.3%.

As of its May 2026 balance sheet, the company maintains a current ratio of approximately 10.3x. The current ratio measures a firm's ability to cover short-term debts with short-term assets, with a higher number generally suggesting better liquidity. The debt-to-equity ratio is roughly 0.0x, indicating the company holds negligible debt relative to its shareholder equity while free cash flow was nearly -$5.4 million.

The case for C3.ai

C3.ai builds enterprise software that allows large organizations to develop and run artificial intelligence applications at scale. The company focuses on industries with complex data needs, such as oil and gas, defense, and manufacturing, through partnerships with Baker Hughes and Shell. It is currently transitioning toward a consumption-based pricing model to attract more customers and improve long-term adoption.

In FY 2026, revenue reached approximately $250.3 million, which is a decline of nearly 35.7% from the prior year. This lower top-line performance resulted in a net loss of close to $470.4 million. The net margin for the fiscal year was roughly -187.9%, suggesting that expenses significantly outpaced revenue during this period of business transformation.

As of the April 2026 balance sheet, the current ratio stands at approximately 6.6x. The debt-to-equity ratio is roughly 0.0x, meaning the company has a clean balance sheet with no significant debt compared to equity. Free cash flow for the year was nearly -$190.7 million, reflecting the cash used by the business for operations and capital investments after subtracting essential spending.

Risk profile comparison

Aehr faces high revenue concentration, meaning the loss of a single major client could severely hurt the business. It also navigates intense competition from larger rivals with more resources in the chip-testing market. Rapid technological shifts could make its current systems obsolete if it fails to innovate quickly, and geopolitical tensions in China and Taiwan present risks to its global supply chain.

C3.ai has a history of significant net losses and persistent operating deficits with no clear path to immediate profitability. The company faces stiff competition from major cloud providers like Microsoft, Amazon, and Alphabet. Revenue is heavily dependent on a few high-value contracts, and evolving regulations such as the EU AI Act could introduce new compliance hurdles for its software platform.

Valuation comparison

C3.ai carries a lower P/S ratio than its peer, though C3.ai does not currently have a meaningful or positive forward P/E ratio because the company is projected to log net losses through fiscal year 2027.

Valuation metrics sourced from Financial Modeling Prep (FMP) and may differ from other data providers.

Which stock would I buy in 2026?

I'd go with Aehr Test Systems, and it's not close. C3.ai's own CEO described recent sales performance as "unspeakably horrible" and "surreal.” That’s not exactly the language you want to hear from a company trying to convince investors that the worst is behind it. Revenue has fallen sharply, and the company has cut roughly a third of its workforce. Analysts expect further declines ahead. A top-to-bottom sales reorganization is underway and may eventually pay off, but right now this company is struggling.

Aehr Test Systems is running a tighter, more focused operation and delivering results that back it up. The company just reported record quarterly bookings, a record backlog, and guided for revenue growth of roughly two to three times its current level in the coming fiscal year. Its burn-in testing equipment is becoming increasingly critical as AI chip complexity grows, and demand is accelerating across AI processors, silicon photonics, and power semiconductors.

For a long-term investor, Aehr offers a clear growth trajectory backed by a record backlog. C3.ai is still trying to find its footing.

Sara Appino has positions in Amazon. The Motley Fool has positions in and recommends Alphabet, Amazon, and Microsoft. The Motley Fool recommends C3.ai. The Motley Fool has a disclosure policy.