How HSP GRUPPE builds AI capabilities for tax advisory

The usage figures in this story refer to the shared ChatGPT Enterprise workspace used by HSP GRUPPE and Kanzleipakt, covering 81 organizational groups. HSP GRUPPE itself is a network of legally independent tax advisory, auditing, and law firms.

For more than two decades, HSP GRUPPE ⁠ (opens in a new window) has consistently invested in digitizing and standardizing professional firm processes. Long before generative AI, the firm network standardized processes, embedded quality management, and fostered a culture of continuous improvement across the network.

When ChatGPT emerged, HSP saw more than another productivity tool. It saw an opportunity to rethink how professional work itself could evolve.

The organization introduced ChatGPT Enterprise with a strong focus on adoption, governance, and continuous learning. Monthly AI forums gave employees a place to share practical use cases and learn from one another. ChatGPT Enterprise’s security features provide an important technical foundation, while the use of client-related information is governed by HSP’s internal data protection, confidentiality, and governance requirements. Professional review and final responsibility always remain with the relevant tax, legal, or accounting professional.

Across the firm network, professionals quickly found new ways to apply AI to their daily work, while the organization also began standardizing successful use cases into custom Agents. One example is AI Client Communication , a shared Agent that supports first drafts, structure, clarity, and a more consistent, client-oriented tone. Professional review and final responsibility remain with the relevant tax, legal or accounting specialist. Another is the Booking Assistant SKR03 & SKR04 , which supports the preparation and classification of specific booking questions. The final professional decision remains with the employee. Together, these kinds of shared Agents reduce repetitive work while making best practices available to every employee—not just AI experts.

For Schulz, the opportunity isn’t simply helping people complete existing tasks more quickly. It’s redesigning the workflow itself.

A deliberately conservative internal scenario estimates approximately 40,000 hours of additional annual capacity. Around 28,000 hours could support productive, generally billable specialist work, while roughly 12,000 hours could support administration, client service, and support. Based on conservative hourly rates, HSP estimates a theoretical annual revenue potential of approximately €3.8 million. This is a capacity scenario—not realized or guaranteed revenue.

Together with Kanzleipakt, HSP GRUPPE plans to establish a joint DATEV-centric AI, firm process, and development team to evaluate successful decentralized experiments and translate them into documented, scalable reference workflows. As ChatGPT Work and agentic capabilities mature, HSP plans to move beyond assisting individual professionals toward automating entire workflows that proactively support employees and clients alike.

Rather than asking how AI could help employees write faster emails or summarize documents, leadership asked a broader question: What happens when AI becomes part of the operating model of a professional services firm?

That vision led HSP to embed ChatGPT Enterprise into tax advisory, legal research, client communication, financial analysis, and knowledge sharing across the firm network.

HSP approached AI as an organizational transformation rather than a software rollout.