Zeiss, the German optics maker that supplies the lenses inside ASML’s most advanced chipmaking machines, just scrapped its original plan for moving to SAP’s cloud software after the bill climbed past €200 million, according to people familiar with the matter. That’s not a rounding error even for a company Zeiss’s size, and it explains why the company changed course.
Zeiss originally chose what’s called a greenfield approach, essentially rebuilding its core IT systems from the ground up in the cloud rather than just migrating what already existed. The pitch behind greenfield projects sounds appealing: you strip out years of accumulated legacy complexity and start fresh. In practice, though, people familiar with the project said it proved more complicated than Zeiss expected, so the company pivoted to a brownfield approach instead, migrating its existing systems rather than rebuilding them, with external consultancies now leading the work.
This kind of stumble isn’t unique to Zeiss. SAP has pushed customers toward cloud subscriptions since 2020, and that shift now makes up more than 60 percent of the company’s revenue. But cloud migrations remain genuinely hard, and Zimmer Biomet’s lawsuit against Deloitte last year shows what can go wrong: the medical tech company claims it paid $94 million, 36 percent more than quoted, for what its complaint calls “an overly customized software system riddled with defects.” Deloitte disputes the claim.
Cost estimates from Byron Ford, a consultant at Berkeley Partnership, put the gap in real numbers. Greenfield projects typically cost at least 20 percent more than brownfield ones, and sometimes double the price, depending on how many countries and systems the project touches. A single-country greenfield migration can cost £35 million to £40 million, while a global rollout often runs double that or more.
Zeiss began this migration six years ago and says the new approach will help it move faster, though a company spokeswoman declined to discuss the actual cost or timeline. Meanwhile, the company keeps expanding its semiconductor optics business to meet demand from chipmakers building hardware for Nvidia and others, which makes the timing of this IT overhaul anything but incidental.

