According to a report in news.com.au, the 30-year-old has turned an investment of $100,000 in mattress retailer Koala Mattress, into a windfall of $12.1 million.
The report quoted The Australian Financial Review (AFR) according to which the company, in which Smith dropped the investment for 10 per cent in July 2015, has build a customer base of 200,000 and is valued at $150 million.
"I remember telling his manager and his parents that could happen when he invested," Koala co-founder Mitch Taylor said.
Smith, who is also Koala's brand ambassador, has earned more from his investment in the company than from cricket altogether.
The AFR's Young Rich List is set to value Smith at about $31 million when the list is released in October.
Smith, who was banned for an year for his involvement in the Sandpaper Gate fiasco, has met with success both on and off the field.