ASML can sell more chipmaking capacity without selling another new machine.

In Q3, $ASML 's service and field-option sales reached €3.289B, up 19.1% from Q2. Management says demand for productivity upgrades helped lift company-wide gross margin to 57.5%.

The opportunity: earn more from equipment customers already own, alongside new-system sales.

But upgrades aren't a guaranteed subscription, and customer expansion plans aren't orders.

I'd watch repeat service-and-upgrade demand and cash generation through the cycle. Slowing customer utilization or weaker upgrade demand would weaken the thesis.