Czech businessman Michal Strnad has seen his fortune rise to $37 billion after the stock market listing of his defense company Czechoslovak Group (CSG).

According to the Bloomberg Billionaires Index, the 33-year-old is now the world’s richest defense-industry entrepreneur and ranks third among the planet’s wealthiest people under 40. He trails Lukas Walton of the Walmart Inc. family (about $49 billion) and Mark Mateschitz, the son of the Red Bull founder (about $38.4 billion).

Strnad inherited CSG from his father. He became the company’s chief executive at 21 and took ownership five years later.

On Friday, CSG completed an IPO on Euronext Amsterdam worth €3.8 billion, valuing the company at €25 billion. During trading, CSG shares were up as much as 32% at one point.

CSG is among Europe’s leading producers of artillery ammunition for NATO countries and Ukraine. After buying the US-based Kinetic Group for $2.2 billion last year, it also became one of the world’s top manufacturers of small-caliber ammunition for handguns. The company is also rapidly expanding its heavy equipment business, including the production and modernization of artillery systems, armored vehicles, and military trucks. CSG employs around 14,000 people.