A tax firm gave all staff ChatGPT Enterprise — 98.6% say they're more productive

Professional services firms are built on billable hours, expertise, and trust. HSP GRUPPE, a network of German tax advisory, auditing, and law firms, just dropped a data point that should make every managing partner sit up straight: after rolling out ChatGPT Enterprise across 81 organizational groups, 98.6% of employees reported higher productivity. Not a pilot team. Not a tech-savvy splinter group. Nearly everyone.

The numbers are genuinely staggering for a sector this conservative. Over a six-month period from February to July 2026, the workspace logged more than 500,000 ChatGPT conversations. Weekly active usage hit 84%. The firm estimates this has unlocked 40,000 hours of additional annual capacity — and they’re not using it to cut staff. The network is already running at capacity with substantial backlogs. Instead, professionals are redirecting those hours toward advisory work and client relationships.

What makes HSP’s approach interesting isn’t the technology itself, but the implementation philosophy. Leadership didn’t treat this as a software rollout. They treated it as an operating model transformation, complete with monthly AI forums, custom shared Agents, and governance that keeps professional review and final responsibility squarely with the human expert. One custom Agent handles client communication drafts for clarity and consistent tone. Another assists with booking classifications under German accounting standards SKR03 and SKR04. Managing Partner Frank Heibel describes ChatGPT as a “genuine sparring partner” for complex tax questions — a phrase that captures the shift from automation tool to cognitive collaborator.

Concrete time savings are already surfacing. Partner Magdalene Posnak reduced the work of evaluating multiple real estate investments from roughly nine hours to about two. That’s not marginal improvement; it’s a structural change in how a professional allocates their most constrained resource. The firm is now piloting ChatGPT Work with a small developer group, exploring how agentic AI might safely automate more complex workflows while balancing governance and cost. For an industry built on credentialed judgment, the question HSP is asking isn’t whether AI can replace professionals. It’s what those professionals become when they’re freed from seven hours of prep work per deal.