OpenAI HSP GRUPPE AI rollout for tax advisory

TL;DR

HSP GRUPPE integrated ChatGPT Enterprise into its tax advisory, legal, and audit processes, reaching 84% weekly active usage and delivering up to €3.8 million in theoretical annual revenue potential by shifting AI from a productivity tool to an organizational capability.

Reinventing Professional Work

HSP GRUPPE, a network of independent tax, audit, and law firms, has a two‑decade history of digitizing and standardizing its operations. When ChatGPT became available, the firm’s leadership chose to treat AI as a catalyst for re‑thinking the entire operating model rather than merely a speed‑up for routine tasks.

“Technology is moving faster than organizations can transform. Our challenge wasn’t introducing AI—it was helping the organization absorb it.” —Carsten Schulz, CEO, HSP GRUPPE

Organizational Rollout Strategy

• Adoption‑first mindset – Monthly AI forums let employees share use cases and learn from peers.
• Governance and security – ChatGPT Enterprise’s built‑in security met HSP’s internal data‑protection and confidentiality rules; final professional responsibility always remained with the qualified tax, legal, or accounting specialist.
• Scalable agents – Successful experiments were codified into shared agents such as:
  • AI Client Communication – Drafts client‑facing text with consistent tone and structure.
  • Booking Assistant SKR03 & SKR04 – Helps classify bookkeeping entries while leaving the final decision to the employee.

These agents reduce repetitive work and disseminate best practices across all 81 organizational groups in the shared workspace.

Real‑World Impact on Professionals

• Technical sparring – Managing Partner Frank Heibel uses ChatGPT to explore complex tax questions, describing it as a “genuine sparring partner.”
• Time‑saving analysis – Partner Magdalene Posnak cut the evaluation of multiple real‑estate investments from nine hours to about two, freeing time for client advisory.
• AI‑powered dashboards – Managing Director Marco Sell employs dashboards to co‑explore financial scenarios with clients during meetings.
• Judgment augmentation – Lawyer and tax advisor Jan‑Henrik Leifelt uses ChatGPT to strengthen, not replace, his professional judgment.

The common outcome: significantly less preparation time and more time applying expertise.

“An analysis of several real estate investments used to take me around nine hours. With ChatGPT, I can prepare it in about two—and use the time saved for client advisory.” —Magdalene Posnak, Partner, HSP GRUPPE

Preparing for the Next Wave with ChatGPT Work

HSP began piloting ChatGPT Work with a small developer group before scaling. The aim is to evaluate agentic AI for safely automating complex workflows while preserving governance, quality, and cost controls.

• Capacity focus – The firm is not targeting headcount reduction; instead, saved time is redirected to additional client work, shorter turnaround, and higher advisory capacity.
• Workflow redesign – Example: continuous bookkeeping review that proactively requests missing documents, moving AI from assistance to orchestration.

“We identified 88 opportunities for automation. But I think that’s already thinking too small. The real question isn’t how we automate today’s processes. It’s how we redesign them. That’s what opens the door to a completely new world.” —Carsten Schulz, CEO, HSP GRUPPE

Quantitative Results (Feb 1 – Jul 14 2026)

Metric	Value
Weekly active usage	84% (755 users)
Unique users	913
Messages exchanged	> 500,000
Employees reporting higher productivity	98.6%
Employees reporting higher work quality	84.6%
Weekly time savings reported	95.9% (63.5% saved ≥ 2 h, 25.7% saved ≥ 5 h)
Improved client service	79.7%
Higher job satisfaction	78.1%
Conservative capacity estimate	~40,000 h additional annual capacity
Theoretical revenue potential (conservative rates)	≈ €3.8 M

The capacity estimate translates to roughly 28,000 h of billable specialist work and 12,000 h for administration and client service.

Leadership Lessons

1. Treat AI as an organizational capability – Scale repeatable workflows, not isolated experiments.
2. Invest in operational foundations first – Governance, security, and quality systems accelerate adoption.
3. Cultivate continuous learning – Regular AI forums spread successful ideas quickly.
4. Redesign workflows, not just tasks – End‑to‑end process re‑engineering yields the greatest value.
5. Anchor AI to professional judgment – AI augments expertise rather than replaces it.

Practical Tips for Other Firms

• Start with concrete business problems, not AI feature lists.
• Host regular cross‑team forums to share use cases.
• Pair AI specialists with domain experts to turn pilots into scalable workflows.
• Pilot new capabilities with small groups before organization‑wide rollout.
• Measure adoption and business impact, not just deployment metrics.

Future Roadmap

HSP and its partner Kanzleipakt will create a joint DATEV‑centric AI team to consolidate decentralized experiments into documented, scalable reference workflows. As ChatGPT Work matures, the focus will shift from assisting individual professionals to automating entire end‑to‑end processes that proactively support both employees and clients.

“Everyone talks about AI replacing tax advisors. I think that’s the wrong conversation. The real opportunity is helping qualified professionals become dramatically more effective.” —Carsten Schulz, CEO, HSP GRUPPE

The firm believes its most significant AI gains are still ahead, with the potential to transform how trusted professionals deliver value in tax advisory and related services.