Both revenue and profit exceeded expectations, but the guidance was disappointing; Arista's stock price plunged.

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Performance far exceeded expectations, but profit margin guidance hit the brakes—Arista traded a "good but not good enough" earnings report for a drop of over 12% after hours.

After the US stock market closed on May 5 local time, “the leading switch maker” and network equipment manufacturer Arista Networks announced its Q1 2026 earnings report. The figures were impressive: both revenue and profit exceeded Wall Street expectations. But the market reacted very differently—the stock plunged nearly 14% after hours, breaking below $148, far lower than that day’s closing price of $170.22.

The problem lies in the profit margin guidance.

The performance itself isn't an issue

Data shows that Arista's first quarter (ending March 31) revenue reached $2.71 billion, up 35% year-on-year; adjusted earnings per share came in at $0.87, up 34% year-on-year.

Both figures exceeded analyst expectations—according to FactSet, Wall Street had previously forecast revenue of $2.62 billion and earnings per share of $0.81.

Non-GAAP gross margin for Q1 was 62.4%, also within the company’s previously provided guidance range of 62% to 63%.

Arista CEO Jayshree Ullal commented after the report: "Arista had a strong start to Q1 2026, with leading performance and industry-leading net promoter scores. We have unique advantages across secure client, campus, cloud and AI networking."

Guidance “just meets expectations,” the market isn't buying it

Arista's Q2 revenue guidance is about $2.8 billion, basically in line with FactSet’s analyst estimate of $2.78 billion. Adjusted earnings per share guidance is about $0.88, also slightly higher than the $0.86 expected.

Looking at these numbers alone, the guidance doesn't seem bad.

But what really unsettled investors was the profit margin. Arista expects adjusted operating margin for Q2 to be 46% to 47%—this range is lower than last year's Q2 (48.8%), and also lower than the recently ended Q1 (47.8%).

Falling profit margin means the company’s profitability is declining. For a tech stock with a lofty valuation, this is a sensitive signal. According to Investor's Business Daily, in a context of high expectations, "guidance that only meets expectations" is enough to trigger selling.

A beneficiary of the AI infrastructure boom, but competition pressures cannot be ignored

Arista’s core business is providing network switches to data centers, accelerating internal data transmission for cloud computing and AI infrastructure.

Over the past two years, as tech giants like Microsoft, Meta, Google, and Oracle massively expanded their AI data centers, Arista became a direct beneficiary—the stock has risen about 150% cumulatively in two years.

Among the highlights in Q1, Arista launched the XPO high-density liquid-cooled pluggable optical module, which the company says can reduce the number of network racks by up to 75%, saving up to 44% of server room floor space, suitable for next-generation AI data centers. Additionally, the company introduced a "Universal AI Backbone" product based on its 7800 series.

On the customer side, reports indicate Arista’s two largest clients are Microsoft and Meta, with Google’s parent company Alphabet and Oracle being newer customers. On April 22, Evercore ISI analysts noted that Google’s newly launched "Virgo" network architecture is highly aligned with Arista’s core product positioning, and believe Arista has the potential to benefit.

However, there are also concerns. According to reports, some on Wall Street worry that Arista may be handing over part of its business to contract manufacturers such as Celestica, and competitors like Cisco Systems and HPE's Juniper division continue to put pressure.

The stock has surged a lot, what does this drop signal?

As of Tuesday’s close, Arista’s stock has gained about 32% for the year, and is up over 87% in the past 12 months.

Big gains mean high expectations. When a company’s stock price has already priced in a lot of optimism, any news that's "not surprising enough" can trigger profit-taking. This time, the catalyst was the drop in profit margin guidance.

After hours, the stock price once dropped to about $149, a decline of over 12%.

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