Supermicro and Arista Beat Estimates as AI Data Center Demand Holds

Investors have been jumpy about AI infrastructure stocks this year, and a single strong quarter can change the mood quickly. Supermicro and Arista Networks both delivered one. Their guidance for the next quarter may matter more than the results they just reported, because it shows how much management expects demand to hold.

Supermicro's sales nearly quadrupled

Supermicro reported fiscal 2027 first-quarter sales of $19.95 billion, against Wall Street's expectation of $17.35 billion. Revenue rose 298% from a year earlier, so the server maker's top line is now roughly four times its size in the same period last year. Earnings before certain costs, including stock compensation, came in at $1.81 per share. Analysts had expected $1.23. After hours, the stock climbed more than 6%.

The number I'd focus on is gross margin. It reached 12.8%, up from 9.3% a year earlier. That's a notable result for a company that builds hardware, where growth often comes with thinner profit per dollar sold. Investors had been worried that rising component costs would squeeze profitability as volumes climbed. The margin moving up instead suggests pricing and product mix are holding better than the skeptics expected. That said, one quarter doesn't settle the question, and margin trends in hardware can reverse when input costs or customer terms shift.

The guidance was the stronger signal. Supermicro expects second-quarter earnings of $1.66 to $1.90 per share on sales of $19.5 billion to $21.5 billion. Analysts had been modeling $1.14 per share and $18.1 billion. Even the low end of the sales range sits close to what the company just delivered, which tells you management isn't planning for a slowdown. Chief Executive Charles Liang said the company keeps selling its servers and storage systems as fast as it can build them, and described its shift toward being "a total AI and IT data center solution provider" as accelerating.

Arista's growth rate stands out

Arista's third-quarter revenue reached $3.66 billion, up 58% from a year earlier and well ahead of the $3.33 billion Wall Street expected. Earnings came in at $1.20 per share against a $1.08 estimate. The stock rose more than 9% in late trading.

The 58% jump is the fastest year-over-year revenue growth the company has posted since its 2014 public listing, and it's a rare figure for a networking vendor of this size. Arista's guidance points to more of the same. For the fourth quarter, the company expects earnings of $1.26 to $1.30 per share, with sales of about $3.95 billion at the midpoint. That midpoint implies growth of roughly 59%, which would set a new high for the company if it holds. Analysts had been looking for $1.16 per share and $3.65 billion in sales.

Chairperson and Chief Executive Jayshree Ullal said even she was surprised by how well the company performed in the quarter. "This strong momentum across customer sectors highlights our increased relevance for the generative and agentic AI era," she said. Her comment points to demand spreading beyond a single customer group, which is a healthier sign than growth concentrated in one buyer segment.

Why networking matters in AI clusters

Arista's business sits in a different part of the stack than Supermicro's, but the two are tied together. Training and running large models depends on clusters of graphics processing units that need to exchange data constantly. The networking fabric connecting those chips affects how quickly they can work together, and as clusters grow, switching and interconnect equipment becomes a bigger share of the total build. Arista supplies much of that equipment, which is why its results track closely with how fast data center operators are expanding AI capacity.

Supermicro sits at the server and storage layer, where it assembles complete systems for those same operators. When a company sells both the compute boxes and the networking that links them, it benefits from the whole build-out rather than a single component. That's one reason both companies can post large growth figures at the same time.

Where the risks sit

Strong numbers don't remove the exposure. AI infrastructure demand depends heavily on a small number of large buyers, and when those buyers adjust spending plans, suppliers feel it fast. Component availability and cost are a live issue for hardware makers, and Supermicro's margin recovery could be tested if supply tightens again. Revenue growth also gets harder to sustain as the base gets larger. Going from 58% growth on today's base to the same rate on a much bigger base requires a steady stream of new orders.

Guidance is also a forecast, not a result. Both companies have set expectations above consensus, and that raises the bar for the next report. A miss against a high bar can hit a stock as hard as a beat lifts it, which is why the stock moves after these reports can swing sharply.

What to watch next

The next two quarters will show whether these results were a peak or a new baseline. For Supermicro, the key number is whether gross margin holds near 12.8% as volumes increase. For Arista, the test is whether the roughly 59% growth implied by its fourth-quarter midpoint shows up in reported sales. If both hold, the case that AI data center spending is still accelerating gets stronger. If margins slip or growth decelerates while guidance stays high, investors will have a harder time looking past the spending concerns that made the sector volatile in the first place.