What is the fine-grained topic of the following text: In companies with world-class IT departments, back-office functional groups such as finance, human resources and procurement were able to save between $2.1 million (£1.8m) and $5.5m (£2.8m) for every $1 billion (£514m) in revenue. Only return the topic.
Cost savings in back-office functions through world-class IT departments