The deal would reportedly expand the firm's presence in Europe and boost its infrastructure exposure.
The private debt specialist, which operates a dedicated secondaries strategy, has reportedly held talks with several international investors.
The passive minority investment will reportedly strengthen the Swiss private equity firm's balance sheet and support team expansion and alignment with LPs.
A non-binding term sheet also gives O3 the option to increase its ownership in the Hungarian fund manager if AUM grows significantly.
The deal marks the sixth investment made by Armen's inaugural GP stakes fund, which targets a portfolio of European alternative asset managers across different strategies.
The 15-asset vehicle, among the largest GP-led infrastructure deals to date, drew more than $7 billion of demand and included around $2.5 billion of new capital.
The deal, which includes future fund commitments, expands Temasek's exposure to Italy's mid-market.
The partnership will also develop products for wealth investors, beginning with an evergreen private equity secondaries fund expected in the coming weeks.
The potential vehicle follows Antin's July agreement to sell ~30% of the asset to GLIL Infrastructure from its €3.6 billion Fund III.
The Swiss manager will acquire ownership in the pan-Nordic data center platform through its infrastructure secondaries strategy.
