Quorum Cyber has signed a definitive agreement to acquire Ontinue from EQT, combining two Microsoft-focused cybersecurity companies serving customers across Europe, the United States and other regions. Ontinue provides 24/7 managed extended detection and response through its proprietary ION platform, which uses agentic AI and automation across the Microsoft security ecosystem. The company serves more than 250 enterprises, NGOs and institutions. Ontinue was carved out of Open Systems as a standalone business in 2023, and EQT says it has approximately doubled in scale under its ownership while consolidating three technology platforms and completing three add-on acquisitions in data science, AI and cybersecurity services. The proposed combination would broaden Quorum Cyber's capabilities across managed detection and response, proactive risk reduction, incident response, professional services and AI-first security operations. Eterna Growth Partners would become the majority investor in the combined company. The transaction remains subject to customary closing conditions and required approvals, and financial terms were not disclosed.