Mark Cuban compared the cryptocurrency boom to the dot-com bubble.
In a string of tweets he recommended buyers hedge their bets.
He warned them about the dangers of debt in a string of tweets this week.
"Watching the cryptos trade, it's EXACTLY like the internet stock bubble."
Cuban sold his startup to Yahoo in 1999.
He managed to protect his billion-dollar windfall when the market crashed a few months later.
"My advice? Learn how to hedge," he tweeted.