Substairs

Substairs

Substairs was founded in Paris to manage the capital of the Multrier family, whose wealth originates from industrial and financial services enterprises established by the family across France. Guillaume Multrier leads the office's investment activities, maintaining a low public profile consistent with the privacy preferences of continental European family offices. The office operates from its Paris headquarters and has not publicly disclosed its total assets under management or detailed family wealth narratives. The office pursues a multi-asset investment strategy that spans private equity, venture capital, and real estate. Its private equity activity focuses on direct investments in mid-market French and European companies, with a preference for control or significant minority positions. In venture capital, Substairs backs early-stage technology companies primarily across Europe. The real estate portfolio consists of direct property holdings — predominantly office and retail assets in central Paris — along with selective development projects. The firm structure allows for flexible deployment through direct equity, co-investment, and limited partner commitments to like-minded fund managers. Geographic concentration remains weighted toward France, with opportunistic exposure to broader European markets. The office maintains a lean team structure typical of single-family offices focused on direct investment rather than capital raising. Operations are conducted from its Paris base, with no publicly disclosed satellite offices. The Multrier family's broader activities include known philanthropic interests in arts and cultural preservation tied to Parisian institutions, though these are managed through separate charitable entities distinct from the investment office. In recent operational context, the firm has continued to deploy capital through its established direct-investment channels, reflecting a long-term, patient posture toward portfolio construction rather than fundraising cycles. Substairs' defining structural characteristic is its posture as a pure single-family investment office that does not manage third-party capital. This permanently aligns its investment horizon with the family's multi-generational wealth transfer goals, eliminating the duration mismatches that constrain institutional fund managers. Its operational footprint — concentrated on direct European mid-market exposure without dedicated sector specialists — reflects a governance approach where principal-level decision making substitutes for layered investment committees.