AIG and McGill and Partners have entered into a collaboration that will use AI to manage the deployment of insurance capacity across the broker's specialty portfolio, in a deal that could reshape how follow underwriting operates in the subscription market.
Under the arrangement, AIG conducted an analysis of McGill and Partners' specialty book and developed underwriting criteria to enable real-time underwriting through the broker's digital platform.
AIG expects to deploy capacity of 25% across up to $1.6 billion of McGill and Partners' gross premiums written specialty portfolio.
In the subscription market, large commercial risks are typically shared among multiple insurers. A lead underwriter prices the risk and sets terms, while follow underwriters decide whether to take a share of the placement at those conditions.
Completing a placement by gathering enough follow capacity has traditionally been slow and labor-intensive, but algorithms can increasingly handle the follow decision, since the risk has already been assessed and priced by a lead.
The collaboration relies on the digital infrastructure McGill and Partners has built since launching in 2019. The broker's platform provided the data access that allowed AIG to evaluate the portfolio and establish an agentic AI framework to manage performance going forward.
AIG worked with Palantir to build what is known as an ontology of the broker's portfolio using Palantir's Foundry platform. In practice, an ontology translates raw data into a structured map of how entities, risks, and relationships connect, allowing AI systems to reason about them.
The system is designed to generate near real-time insights on exposures, limit deployment, modeled risk outputs, and loss information.
The deal is not AIG's first use of the technology. In December 2025, AIG partnered with Amwins and Blackstone to launch Lloyd's Syndicate 2479, deploying Palantir's Foundry and multiple large language model agents to analyze millions of data points across a delegated authority portfolio.
AIG said at the time that it had developed an ontology covering more than four million industry data points.
The insurer has also been scaling AI across its core operations. AIG's Underwriting by AIG Assist tool has been rolled out to seven lines of business, with Lexington recording a 26% increase in submission counts and a 35% improvement in its submit-to-bind ratio for middle market property.
The AIG deal is the latest in a series of digital capacity partnerships for McGill and Partners. In December 2025, the broker launched a similar arrangement with AEGIS London using its proprietary Underscore broking platform for automated quoting and binding on a follow basis. McGill had earlier struck a comparable deal with AXA XL.
Steve McGill (pictured above, left), CEO of McGill and Partners, said the collaboration could disrupt the dynamics of the subscription market, strengthening the value proposition of leading underwriters while redefining how capacity is positioned for clients.
AIG chairman and CEO Peter Zaffino (pictured above, right) said the rapid evolution of AI and large language models is reshaping risk analytics. He added that AIG sees "significant opportunity to deliver greater efficiency to the subscription market while giving clients easier access to high-quality insurance solutions."
