At 16, Michigan student spent $3,500 on Rolex; 5 years later, his watch business topped $10 million

At 16, Michigan student Mason Maressa spent his $3,500 savings on a vintage Rolex Air-King and sold it days later for about $4,000.

He reinvested the money into more watches and gradually built Clocked In.

Five years later, the 21-year-old says his appointment-only luxury watch business in Grand Haven has crossed $10 million in cumulative sales.