Marsh has launched Stratus, a property insurance exchange designed specifically for the operational risks of digital infrastructure projects, including data centers and their associated critical support systems.
The exchange provides access to up to $10 billion in property insurance capacity on a single placement for the global exposures of US-domiciled companies, drawing on 30 traditional and alternative capital providers who will evaluate each risk individually to determine appropriate support.
Marsh said the structure is intended to help capacity providers better assess, quantify and diversify risk, and specifically to address aggregation concerns that arise once digital infrastructure projects move from construction into operation. Stratus will also draw on Marsh's data and analytics and advisory capabilities to help clients procure customized property coverage as their projects transition into service.
Stratus is built to extend Marsh's existing construction-phase facility, Nimbus, launched in June 2025 as the first insurance facility built specifically for large-scale data center construction. Nimbus has since grown to offer up to $2.7 billion in limits, including delay in start-up and business interruption coverage, and Marsh expanded its offering further in February with Nimbus Casualty, an excess casualty facility addressing the long-term liability exposures data center developers face.
Stratus and Nimbus can be used separately or together, and Marsh said Stratus will initially launch focused on property coverage before expanding into inland marine, cyber and casualty lines, working toward a single point of access for clients across a project's full lifecycle from construction through operation.
Joe Macejak (pictured), Marsh's US property digital infrastructure leader, tied the launch to how quickly risk changes once a project goes live.
"As large digital infrastructure projects shift from construction to operation, the associated risks become larger and more complex, driven by multi-billion-dollar campuses, self-generating power systems, and emerging technologies used in processing units and critical equipment," Macejak said, adding that combining Marsh's engineering data, risk consulting and access to global capital markets was intended to improve both the quality and efficiency of these placements.
The launch responds to a data center insurance market industry analysts expect to expand sharply. Allianz Commercial has estimated global premiums for the sector could rise from roughly $11 billion currently to more than $24 billion by 2030, driven largely by the buildout tied to artificial intelligence workloads.
Industry executives have separately warned that available capacity may struggle to keep pace with the sheer number of projects moving from construction into operation over that same period, a gap Stratus is explicitly designed to help close by drawing in capital sources, including alternative and insurance-linked securities capital, beyond the traditional insurance market alone.
Marsh has reportedly approached around 80 carriers and syndicates globally in building out Stratus, with more than $4 billion in capacity verbally committed so far, representing an estimated 30% to 40% of the total capacity the broker is targeting. Some of the largest hyperscale operators self-insure much of their own risk given balance sheets that rival major carriers, positioning Stratus to serve smaller operators alongside hyperscalers still seeking traditional market capacity. Industry sources have also flagged that emerging power sources for these facilities, including small modular nuclear reactors, are expected to introduce further exposures Stratus and its capital providers will need to underwrite as the technology matures.
For brokers and risk managers working with data center developers and operators, Stratus offers a structured, potentially larger single-placement option specifically for the operational phase, an important distinction from construction-phase coverage, since aggregation risk, where a single insurer's exposure compounds across multiple campuses or projects, becomes a materially different underwriting problem once facilities move into live operation.
As more projects transition from Nimbus-covered construction into service, brokers advising clients through that lifecycle shift will want to understand how continuity between the two facilities works in practice, particularly given Marsh's stated intent to eventually offer cyber and casualty coverage through the same platform rather than requiring separate placements across multiple markets.
