Thirty-Eight Percent From TwoThin moat

In 2025, 38.0% of ASML's total net sales went to its two largest customers¹. For most companies that would be a headline risk; for ASML it is a description of the industry it serves.

The filing is direct about the exposure: sales remain concentrated among a limited group, and the loss of any key customer, or a substantial change in their purchasing behaviour, could have a material adverse effect. It also notes that metrology and inspection customers largely overlap with lithography customers, so ASML's diversification into adjacent products has not diversified its customer base at all — it sells more things to the same few people.

That last point deserves emphasis, because it is the honest limit on ASML's strategy. Expanding the product line is genuinely valuable — it raises revenue per fab and deepens the relationship — but it does nothing about the fact that the number of possible buyers is set by how many companies can afford a leading-edge fab, which is falling rather than rising.

Watch whether the two-customer share keeps climbing. Rising means the leading edge is consolidating further, which is good for ASML's pricing and bad for its risk — and there is no version of this business in which both improve at once.