Major ClientsThin moat

Arista Networks (ANET) — moat facet

Two customers are 42% of revenue and in three years they swapped places — the total hides the movement that matters.

Arista's customer concentration is disclosed plainly and its risks have their own root threat. What the filing shows that the risk discussion does not is movement.

The two largest customers, % of revenue39%202335%202442%2025Individually: one went 21% to 16%, the other 18% to 26%. The total hides the swap.
Two customers are 42% of revenue — and in three years they changed places.

Two customers have each exceeded 10% of revenue in each of the last three years. One end customer represented 16%, 15% and 21% of total revenue in 2025, 2024 and 2023; the other represented 26%, 20% and 18%. Together they were 39% of revenue in 2023, 35% in 2024 and 42% in 2025 — and over that period they changed places. The customer that was largest in 2023 is now the smaller of the two, and the one that was smaller has grown to more than a quarter of the company.

That matters more than the combined figure. A concentration that is stable reflects two mature relationships; one where the composition shifts by five points a year reflects two enormous buyers making independent capital decisions that Arista absorbs. The company's own risk language notes that large customers may receive lower pricing through volume discounts, and may re-assign allocations to multiple vendors.

The rest of the base is genuinely diversifying — Arista describes expanding across media, healthcare, energy, education, manufacturing and industrial customers1 — and it is small against two relationships worth 42%. These pages cover what the concentration buys, what it costs, and how far the diversification has actually got.

Moat trajectory: Narrowing

The two largest customers went from 35% of revenue to 42% in a single year, so concentration rose even as Arista expanded its enterprise base. More telling is that the composition shifted: the 2023 leader is now the smaller of the two. A customer base where five points of revenue migrate between buyers annually is not stabilising.

The number that tests this moat
Reported
Share of revenue from the two largest customers
42% in 2025, from 35% and 39%

One end customer was 16%, 15% and 21% across 2025, 2024 and 2023; the other 26%, 20% and 18%. The total hides that they swapped places. Watch both percentages separately — a customer moving five points in a year is the useful early warning.

Source: Arista Form 10-K, FY2025 ↗
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References
  1. ReportedOne end customer was 16%, 15% and 21% of revenue across 2025-2023 and the other 26%, 20% and 18%; the filing notes large customers may receive volume discounts or re-assign allocations to multiple vendors, and describes enterprise diversification.
    Arista Networks Form 10-K, FY2025 — two customers accounted for more than 10% of total revenue in each of the last three years; sales to one end customer represented 16%, 15% and 21% of total revenue and sales to the other end customer represented 26%, 20% and 18% of total revenue for the years ended December 31, 2025, 2024 and 2023 respectively; the company notes unpredictability in the timing and volume of large customer orders, that large customers may receive lower pricing terms due to volume discounts or may elect to re-assign allocations to multiple vendors based upon specific requirements, and that it continues to diversify its enterprise customers across media and entertainment, healthcare, oil and gas, education, manufacturing and industrial sectors — FY2025 (ended December 31, 2025) · publ. February 17, 2026 · source ↗
Sources
Generated September 23, 2026