S/4HANA: greenfield or lift and shift?

The question every CFO asks eventually, and why the honest answer is usually "it depends on your Chart of Accounts, not your appetite for change."

I'm speaking to more CFOs each month who've either just moved to SAP S/4HANA or are about to. The conversation almost always starts the same way: greenfield, or lift and shift from ECC? And it almost always gets answered as if it were a question about risk tolerance, when really it's a question about data.

A lift and shift is attractive because it looks like the safer, cheaper option. You keep your existing configuration, your Chart of Accounts, your customisations, and you move the technical foundation underneath them. In practice, that's only a good idea if what you're carrying across is actually worth keeping.

The real test

Before recommending either route, I look at three things: how tied together the Chart of Accounts is with other structures like cost centres and profit centres, how much of the current configuration reflects genuine business need versus historic workaround, and how confident the organisation is in its own master data.

If the Chart of Accounts has become a dumping ground for reporting requirements that changed five reorganisations ago, lift and shift just carries the mess into the new platform with a shinier interface on top. That's the scenario where greenfield, done properly, pays for itself.

Where greenfield goes wrong

Greenfield's own risk isn't technical, it's organisational. It's an opportunity to redesign, and opportunities to redesign have a habit of expanding to fill the time available. I've seen fit-gap workshops turn into a debate about ideal future-state processes when the actual job was to get a working, compliant finance system live on a fixed date.

The programmes that go well treat greenfield as licence to fix genuine structural problems, not as licence to reopen every process decision the business has ever made. Scope discipline matters more here than in almost any other phase of the programme.

What I tell clients

Start with the data structures, not the timeline. If your Chart of Accounts, cost centres and profit centres are clean and independent of each other, lift and shift is a legitimate, lower-risk route. If they're tangled, greenfield is the more honest answer — but budget the governance to keep it scoped, because that's where the real cost overruns come from.