⚠ Lock-In Cuts Both Ways With Few CustomersModerate threat

Deep customer lock-in is a powerful moat, but with ASML's tiny roster of customers it is also a mutual dependence, and the leverage is not entirely one-sided. ASML is woven into its customers' fabs — but those customers are a mere handful of giants (TSMC, Samsung, Intel¹ and a few others), and ASML is as dependent on them as they are on it. A relationship that binds the customer also binds the supplier, and when the customer is one of only three buyers on earth for your most advanced machines, they wield real negotiating power despite their dependence.

The concentration means the health of ASML's installed-base annuity rests on the fortunes and decisions of very few firms. If a major customer stumbled (as Intel's manufacturing has), slowed its leading-edge investment, or drove a harder bargain, it would ripple straight through both ASML's equipment sales and its service revenue. The lock-in is genuine and mutual, and it has served ASML extraordinarily well — the customers are not going anywhere, because there is nowhere to go. But 'a customer for life' is a two-way vow when there are only a few customers in existence, and the deep ties that protect ASML also concentrate its fate in the hands of a small club of powerful buyers whose own cycles and choices it cannot control.