Short answer
Virtual data rooms are commonly used by banks, law firms, private equity firms, consulting firms, corporates, startups, and financial institutions that need to manage confidential document workflows.
Expanded answer
Common use cases include M&A due diligence, IPO preparation, fundraising, loan documentation, restructuring, litigation support, board communication, and cross-border transactions.
The common requirement is controlled access to sensitive files, especially when multiple internal and external stakeholders are involved.