There is no single correct model. A group of closely related businesses may centralise much more than a diversified group with very different operations. The useful question for each HR activity is: does consistency across the group add more value than local flexibility?
What often works centrally
Grading framework. A common grading structure lets the group compare roles across businesses, move people between them and govern senior pay.
Executive and senior pay. Pay for top roles in each business is usually reviewed and approved by the group.
Core policies. A group-wide policy set covering conduct, data protection and other compliance areas reduces risk, with local variations where entity rules differ.
HR systems and payroll. Shared systems reduce cost and give the group consistent data.
Talent and succession for critical roles. Group-level visibility of senior talent allows people to move to where they are most needed.
What often works locally
Hiring decisions for most roles, within group frameworks.
Day-to-day employee relations, handled by managers and local HR who know the people.
Pay ranges where businesses operate in different sectors or markets with very different pay levels.
Engagement action planning, using group survey tools but local priorities.
Signs the balance is wrong