The firms have reportedly held discussions over a potential tie-up, which would boost Ares' secondaries AUM closer to the $50 billion mark.
Under the non-binding agreement, O3 may increase its ownership in the social impact investor if certain fund launch and fundraising milestones are met.
The secondary market specialist will remain independently managed by its existing leadership team, with no changes to its investment strategy.
The partnership will allow LIM to broaden its product range and bring mutual funds and ETFs to market for advisers and their clients.
The 2025 SecLink Awards winner has returned $4.6 billion of capital to investors through five strip sales over the past two years.
The GP stakes deal builds on a 2024 strategic partnership, which established Lazard Elaia Capital as a technology-focused private equity investment platform.
Founded by Rob McGrath, Overbay is a Toronto-based private equity secondaries specialist with around $3 billion in AUM.
The deal will expand Mercer's private markets platform, adding expertise in secondaries and evergreen vehicles to its offerings.
Founded by Rob McGrath in 2016, Overbay Capital Partners is a Toronto-based private equity secondaries investor with over $2.5 billion in AUM.
The newly combined entity is expected to double the size of Coller's secondaries business in less than four years.
