The $28 Billion Family That Splits a Retail Empire Between 800 Cousins: The Mulliez

A €28 billion fortune shared among nine hundred cousins. A pact signed in a Belgian hotel in 1955 that makes it structurally impossible for any single heir to walk away. A constellation of more than 130 brands — Auchan, Decathlon, Leroy Merlin, Kiabi, Norauto — generating €100 billion in annual revenue across 62 countries and employing 650,000 people, run by a family so private that Le Monde called their system "shareholder communism" and most of the world has never heard their name. The Mulliez clan is the invisible engine of French retail. ------------------------- Gain FREE access to secret full-length documentaries on wealthy families "too scandalous for YouTube" by joining our newsletter: https://www.substack.com/@oldmoneyluxury ------------------------- It began in 1903 in Roubaix — the textile city known as "the French Manchester" — when a devout Catholic industrialist named Louis Mulliez opened a small wool-twisting mill and started backing his sons and son-in-law in their own ventures, on one condition: every new business had to cross-invest in every other. In 1955, six members of the second and third generations met in Ostend, Belgium, and signed the Association Familiale Mulliez pact, anchored in a single radical principle — "Tous dans tout," Everyone in Everything. Shares could only be held by direct descendants of Louis and Marguerite. Every future business they ever launched would automatically enter the communal pool. Six years later, Louis's grandson Gérard returned from a trip to America, electrified by what he'd seen in U.S. supermarkets, and opened the first Auchan in a converted Roubaix factory — six hundred square meters and thirty employees. Within a decade, it was a hypermarket. Within forty years, it spanned fifteen countries. Decathlon, founded by cousin Michel Leclercq in 1976, now does €16.8 billion a year across 79 countries. Leroy Merlin's parent ADEO turns over €31.5 billion. Kiabi, Norauto, Phildar, and roughly 150 family-created companies all live inside the same legal cage — and an internal stock exchange opens once a year in July so cousins can buy and sell only among themselves. The family's motto is "Silence does good, good does not make noise." They live concentrated in Néchin, a Belgian village 800 meters from the French border, with no wealth tax. Auchan and Leroy Merlin remained in Russia after 2022. In late 2024, the family paid itself a €1 billion Decathlon dividend weeks before announcing 2,389 layoffs at Auchan in France. Gérard Mulliez has given virtually no interviews in six decades. Whether the pact of Ostend is the most brilliant family governance system ever designed or a gilded prison depends entirely on which side of the door you're standing on.