[4] In 2014, magazine La Voix du Nord reported Leclercq's net worth as Euro 1.76 billion.

[5] He is the former chairman of Decathlon, one of the world's largest sporting goods retailers,[6][7] which was founded by his father Michel Leclercq.

[8] Through Olivarius Hospitality California, Leclercq is the sole owner of Coolibar, an industry leader in proprietary sun-protective clothing.

[10] Olivier is the first son of, Michel Leclercq, the founder of Decathlon, the largest sporting good retailer in the world, both of whom are on the board of directors.

in 2018, Bloomberg reported the Mulliez family net worth as US$37.5 billion.