24. Zekelman Family
Net Worth: $3.46 billion
Change from 2017 Ranking: ▲63.2%
Major company holdings: Atlas Tube
The Zekelman family runs the largest independent steel tube manufacturer in North America, and they want everyone to know it: Last year the clan changed the name of the company from JMC Steel Group to Zekelman Industries, Inc. The firm churns out more than 2.5 million tonnes of steel products each year—primarily pipes, large structural steel elements and electrical conduits used in construction.