Lance Armstrong says an early investment in Uber has "saved" his family after paying out $111m in legal fees and
The American, 47, was stripped of his seven Tour de France titles and banned from cycling for life in 2012 before admitting to using performance-enhancing drugs.
He says he gave $100,000 to a venture capital fund that invested in the ride-hailing app in 2010.
"It's saved our family," he told CNBC.
He said Uber, which was founded in 2009, was valued at $3.7m when he invested. The company was valued at $72bn this year and is targeting a valuation of $120bn in 2019.
When asked if he had earned "10, 20, 30, 40 or $50m", Armstrong replied: "It's one of those.
He added that he did not even know he was investing in Uber when he gave the money to associate and entrepreneur Chris Sacca, who started Lowercase Capital in 2010.
"Most people have enough history and knowledge to know everybody did it ," he said.
"That isn't the issue for people - the issue is how aggressively I defended myself, being litigious, going after people.
Armstrong agreed a settlement with The Sunday Times in 2013 having previously been paid to settle a libel case in 2004 after the newspaper alleged he had cheated.