Stefan Wirtgen

Stefan Wirtgen is one of two billionaire brothers who inherited the family fortune from their father, Reinhard, founder of construction equipment maker Wirtgen Group.

Wirtgen group was founded in 1961 and sold to Deere & Company in 2017 for $5.2 billion.

After the sale, the brothers created Wirtgen Invest, a family office with interests in energy, real estate, healthcare, consumer goods and finance.

The investment firm has made some 700 generally passive investments, according to its website.