The Hidden Cost of Waiting: Why Six in Ten S/4HANA Projects Blow Their Budget

A separate piece of research, from the analyst firm ISG, surveyed 200 senior decision-makers at large global companies and published its findings in February 2026. It landed on a strikingly similar headline: nearly 60% of SAP migration projects were delayed, over budget, or both. ISG's researchers also found that fewer than one in five organizations actually reimplemented their SAP processes and technology when they moved to S/4HANA — 49% carried out little or no re- engineering at all, choosing instead to preserve legacy processes and data largely as-is.

That last finding matters more than it might first appear. ISG principal analyst Michael Dornan described a pattern where organizations try to do the fastest, cheapest possible lift-and-shift, then get blindsided by scope creep and changing requirements they hadn't planned for. More than half of ISG's respondents admitted they had over-customized their legacy ERP to a degree that made standardizing now feel genuinely risky to the business — which is exactly the kind of inertia that turns a planned six-month project into an eighteen-month one.

Horváth's researchers trace the root cause back even further, to how these programs get set up in the first place. Three-quarters of the executives they surveyed said the selection and