Solstein Capital

Alexander Klabin, the founder and CEO, is the primary investment decision-maker. He built his career at Senator Investment Group as a co-founder and managing partner, where he was known for a credit-driven, fundamental research approach. At Solstein, he directly oversees all portfolio allocations.

Solstein relies on Alexander Klabin's two decades of relationships from his time at Senator Investment Group, one of the longest-running credit-focused hedge fund platforms. The firm accesses opportunities through direct sponsor dialogue, co-investment circles with other family offices, and existing general partner relationships. The office does not market itself for deal origination.

Solstein is a single-family office managing Alexander Klabin's personal capital. It does not accept outside capital as a fund manager, but it does selectively co-invest alongside trusted partners on a deal-by-deal basis. This structure allows permanent capital flexibility without the redemption or fee pressures of a traditional fund.

The office engages in both. Solstein makes direct investments in private companies and real estate assets, and also commits to third-party funds, particularly in venture capital, private credit, and special-situations strategies where Klabin has long-standing manager relationships.

Across its private market activities, Solstein targets growth-stage venture, late-stage pre-IPO rounds, and direct credit origination. The office does not publicly disclose a specific stage mandate, but observed positions include Series B through pre-IPO companies in enterprise software and fintech.

The wealth derives from Alexander Klabin's tenure as co-founder and managing partner of Senator Investment Group, a $30 billion multi-strategy hedge fund platform he helped build starting in 2008. That firm was known for its credit, distressed, and event-driven strategies, generating substantial carried interest and personal investment returns.

Solstein selectively co-invests alongside external general partners, particularly in private credit and growth equity transactions. Klabin often uses his personal relationships to negotiate co-investment capacity without management fees or carried interest, consistent with his emphasis on structuring favorable economics.