Former Blackstone Duo Closes $400M Debut Fund at 154 Partners

154 Partners, a private equity firm that partners with founders and owner-operators, has held the final close of its maiden fund, 154 Partners Fund I LP, at its $400 million hard cap. Co-founders Isaac Harrouche and Mike Berlin launched the New York-based firm in January 2025 to primarily invest in residential, business, and sports & live event services. 

154 Partners targets profitable private companies generating $2 million to $20 million of EBITDA and pursues control and shared-control investments across its core sectors. The firm expects to deploy $40 million to $100 million of equity per platform investment over its holding period.  

“Our investors share our conviction in the lower-middle market and believe in our partnership-driven approach to structuring transactions that meet the needs of founders and owner-operators,” said Harrouche, Co-Founder and CEO of 154 Partners. 

Harrouche and Berlin began their careers together at Blackstone in its Tactical Opportunities group, working with David Blitzer. Blitzer joins Harrouche and Berlin as the third member of the firm’s Investment Committee, bringing additional experience in sports and live events.  

“Our goal is to balance value creation with capital preservation, helping businesses grow sustainably while honoring what founders have already built,” said Berlin, Co-Founder and CIO. 

Backed by Bolt Ventures and strategic family offices, 154 has already invested in an accounting services consolidation platform and in a sports and live event-focused guest services platform, underscoring its thematic focus on recurring-services business models. 

Morgan, Lewis & Bockius LLP served as legal counsel for the Fund. 154 Partners did not engage a placement agent.