Sud Mer Invest
Sud Mer Invest is a French regional blue-economy fund, wholly owned by the bank Banque Populaire du Sud, that backs maritime and water-management startups across Occitanie and southern France. As of June 2025 it doubled its capital to 7 million euros and widened its mandate from the sea to freshwater. It has backed 2 water companies.
Compiled by Antoine Walter, (don't) Waste Water, from official filings and direct intelligence in Leviathan.
The take
Sud Mer Invest is not a private venture fund at all: it is the captive investment arm of Banque Populaire du Sud, a regional French bank, set up in 2021 to put money into the businesses of its own coastline. Its single backer is the bank itself, which makes it a rare creature in the water world, a regional fund underwritten by one institution rather than a pool of outside investors chasing returns.
Sud Mer Invest began life looking out to sea. Its first cheques went to the maritime economy of the Mediterranean, decarbonising ships, restoring coastal habitats and digitising port logistics, the blue economy built around the water's edge. In June 2025 it widened that mandate to fresh water, and its water bets so far are about treating it close to where it is used: AquaTech Innovation builds modular treatment units for campsites, marinas and small towns, while Greenphage uses bacteriophages, the viruses that eat bacteria, as a biological alternative to chemical disinfection.
Sud Mer Invest does not run its own deal team. The investing is steered by GO Capital, a French manager whose Impact Océan Capital fund specialises in the ocean economy, and the cheques land early, from seed (a startup's first outside money) through Series A (its first large institutional round). It almost never leads a round, preferring to sit alongside regional co-investors such as SOFILARO, IRDI Capital Investissement and Calao Finance rather than set the terms itself.
As of June 2025, Sud Mer Invest doubled its capital to 7 million euros and set a target of 10 million by 2030, with water named for the first time as a reason to grow. That makes the freshwater mandate the thing to watch here: for a newcomer, Sud Mer Invest is the clearest example I track of a regional bank quietly underwriting the early, risky water technology of its own stretch of coast.
Water Commitment Score
Compiled from official filings, third-party records, and direct intelligence from investors and founders, in Leviathan · recomputed monthly · as of Jun 2026.
How they invest
Portfolio · 2 water companies
Invests alongside
Highlighted = profiled on (don't) Waste Water.
Frequently asked
- What does Sud Mer Invest invest in?
- Sud Mer Invest invests in the blue economy of southern France: maritime startups working on cleaner shipping, port technology and coastal ecosystems, and, since 2025, water-management companies. Its water bets focus on treating water close to where it is used, such as modular treatment units for campsites and marinas and bacteriophage-based disinfection.
- Who owns and runs Sud Mer Invest?
- Sud Mer Invest is wholly owned by Banque Populaire du Sud, a regional French bank, and chaired by its president Benoît Viguier. Its investments are steered day to day by GO Capital, the French manager behind the Impact Océan Capital ocean fund, which sources and executes deals on the fund's behalf.
- Where is Sud Mer Invest based?
- Sud Mer Invest is based in Sète, on the Mediterranean coast of Occitanie in southern France, and was created in 2021. It invests across the South of France, the home territory of its parent bank Banque Populaire du Sud, with a focus on the regional maritime and water economy.
- What stage and how big is Sud Mer Invest?
- Sud Mer Invest is an early-stage backer, writing cheques from seed to Series A, a startup's first institutional rounds. As of June 2025 the fund doubled its capital to 7 million euros and targets 10 million by 2030, and it has backed 2 water companies to date.
- Is Sud Mer Invest the same as Mer Invest or Impact Océan Capital?
- Sud Mer Invest is its own fund, the captive vehicle of Banque Populaire du Sud, and should not be confused with Mer Invest or Impact Océan Capital, which are separate ocean-economy funds run by GO Capital. The three often co-invest in the same maritime deals, which is why the names appear together.