Sienna Investment Managers
Asset management subsidiary of Malakoff Humanis
Also known as Sienna IM, Sienna Gestion, Sienna AM France, Malakoff Humanis Gestion d’Actifs
Paris asset manager (AMF GP97020, GP97118) owned by Malakoff Humanis; its private debt business (€2.1bn, June 2026) lends to European SMEs, energy-transition and public-sector borrowers.
French asset manager owned by Malakoff Humanis since 2026; not to be confused with GBL’s former Luxembourg-based Sienna Investment Managers platform (Sienna Capital).
- HEADQUARTERS
- Paris, France
- FOUNDED
- —
- AUM
- —
- OUTSIDE CAPITAL
- Yes
- TEAM LISTED
- 3 people
Focus
- STAGES
- Growth
- ASSET MIX
- Private creditPublic equities
- GEOGRAPHY
- Europe
Overview
Sienna Investment Managers is the brand of Sienna Gestion and Sienna AM France, two Paris portfolio management companies managing about €36bn (30 June 2026) across listed equities, bonds, multi-asset, employee savings, hybrid funds and private debt. The private debt business, about €2.1bn under management for more than 70 institutional investors, finances SMEs and mid-caps, renewable-energy infrastructure, French local authorities and public hospitals, and commercial real estate. Sienna Gestion was formerly Malakoff Humanis Gestion d’Actifs, in which GBL’s Sienna platform took a majority stake in 2022; in May 2026 Malakoff Humanis completed the acquisition of Sienna Gestion and Sienna Private Credit from GBL.
Investment thesis
Private debt funds and mandates for institutional investors as a diversification of bond portfolios: asset-backed junior and senior loans to European SMEs and mid-caps (including the Sienna Héphaïstos defence-industry strategy), energy-transition project debt, loans to the French public sector and senior real-estate debt, plus hybrid funds that combine listed and unlisted assets for retail savers.
People
Links
Frequently asked questions
Sienna Investment Managers is a private equity fund based in Paris, France.
Yes. Sienna Investment Managers invests its own capital in private companies.
Sienna Investment Managers invests at Growth stage in Climate & Energy, Industrial & Manufacturing and Real Estate & PropTech.
Key people at Sienna Investment Managers include Xavier Collot (CEO of Sienna Gestion (appointed 2022; leads it under Malakoff Humanis ownership, May 2026)), Fabrice Rossary (Head of private debt; Président of Sienna AM France) and Philippe Garrel (Managing Director, Energy Transition Debt Funds).
The most recent publicly reported investment by Sienna Investment Managers is Ecopower Limited (100 MW onshore wind project, Ireland) (Junior debt (~€20M)), announced in May 2026.
Yes. Sienna Investment Managers manages capital from outside investors.