Transaction overview

Keystone Capital Management, L.P., a Chicago-based private equity firm focused on professional and tech-enabled services among other sectors, acquired Azzur Labs (now known as Gillson Testing) in January 2025 to form Gillson Sciences. The deal value was not disclosed, but the transaction closed on January 1, 2025. Jason Fischer, formerly of UL Solutions, has been appointed CEO to oversee the company's build-up strategy.

Deal structure and financing

Details of the equity and debt split for the acquisition were not provided in publicly available information. Given Keystone Capital’s history of funding acquisitions with a mix of both sources, it is likely that a combination of private equity capital from Keystone funds and possibly external debt was used to finance the deal. No specific lead banks or advisors have been disclosed. The company has retained its existing management team but introduced Jason Fischer as CEO to drive further growth.

Strategic context

Keystone's acquisition of Azzur Labs, rebranded as Gillson Testing, aimed at consolidating expertise in laboratory testing and advisory services across pharmaceuticals, biopharma, medical devices, healthcare, and environmental sciences. The goal is to establish a comprehensive service provider capable of addressing complex challenges through integrated solutions. Jason Fischer’s background with UL Solutions underscores the strategic importance of corporate development and acquisitions in building market leadership within regulatory compliance sectors.

Regulatory path

The acquisition was reviewed by relevant U.S. antitrust authorities as part of standard procedural requirements for mergers and acquisitions, but no significant remedies or delays were reported. The deal did not require any specific divestitures, indicating that it likely involved markets with low competitive concerns. HSR filings would have been submitted at the appropriate time in late 2024 or early 2025 based on the deal size and jurisdictional requirements.