Because they're not a monopoly based on anticompetitive practices, they're a monopoly because what they do is so difficult and massively expensive that the monopoly is the only thing that makes it economically viable. The worldwide market for these machines is only perhaps a few dozen a year at most, it just can't support paying the R&D bills of multiple competitors.
ASML is also part-owned by their customers. Intel, Samsung and TSMC all invested in ASML to get EUV tech over the line - see aforementioned capital requirements.
Also, it's only really a monopoly at the top end, and only right now. It's not like ASML is the only company building litho machines. Canon and Nikon still sell a lot of machines, they just decided not invest to much into competing at the top end over the last 10 years.
This could, theoretically, change at any moment, and Canon is trying something with their new generation of nano-print tech.
INAL. Antitrust is not against monopoly, but monopoly "abuse". MS is free to make an OS which everyone wants and free to be a monopoly. When they tried to leverage it to gain market share in the distinct market of browser and media players it became a problem.
So till ASML starts abusing the position they should be good legally.
Watch out, different jurisdictions have different 'anti-trust' laws. And, especially in common law jurisdictions, interpretations of a law can also change over time.
The warning is for armchair speculators like you and me. Specifically:
> Antitrust is not against monopoly, but monopoly "abuse".
So this might be true about anti-trust in the US right now. But I'm not sure whether it's true about ant-trust law in eg France?
Also, in practice this was not true about anti-trust law in the US historically: Standard Oil was smashed into pieces without anyone proving in court that consumers had been harmed, or that the monopoly had been 'abused'.
But no worries: in a democracy we expect ordinary people to have some interest in the laws, after all, they are supposed to be electing people who decide on how laws should be changed (or not). So layman need to talk about laws, too.
I'm just always a bit cautious (or at least I should be). I know that eg in the US insider trading is about stealing secret from your employer; but in eg France insider trading is about having an unfair advantage over the public.
I can image that there are jurisdictions that treat monopolies by themselves as a problem. (Perhaps France, again?)
Btw, for the US herself have a look at https://fee.org/articles/the-myth-that-standard-oil-was-a-pr... to see how the prototypical case against Standard Oil wasn't really about monopoly abuse, either. At least no one really bothered proving that a monopoly was abused, they mostly just assumed it.
The relevant EU Law[1] seems to be "Any abuse by one or more undertakings of a dominant position within the common market or in a substantial part of it shall be prohibited as incompatible with the common market insofar as it may affect trade between Member States."
So, as long as it treats fabs in Europe fairly, it can do whatever it wants in the rest of the world.
It's not ASML's fault that 20 years ago when Martin van den Brink (CTO) went full steam to develop EUV everyone laughed at him saying EUV would be impossible to achieve. Their monopoly is well deserved. Other companies have a few years to catch up for full fault of their own.
ASML is also part-owned by their customers. Intel, Samsung and TSMC all invested in ASML to get EUV tech over the line - see aforementioned capital requirements.