Investment guru Ron Insana said this whole public craze about the controversial digital currency bitcoin reminds him of the dotcom bubble.

And the greatest lesson he learned was that in such a situation, "the last person into a speculative frenzy such as bitcoin never gets out before it's too late," the author of four books on Wall Street explained.

"At the height of the internet bubble, some of my colleagues and I were trying to decide if we should remain as business journalists on cable television, or join some of our colleagues in start-up dot.com ventures that focused on web-delivered business news," he wrote for CNBC.com.

"Thankfully, many of us were bound to contracts and couldn't simply leave our posts to join the young and restless," the CNBC and MSNBC contributor wrote.

"One of our colleagues, from another service, had joined a start-up business site and was worth $9 million the very first day that dotcom went public," Insana wrote.

"When he left a couple years later, that $9 million was worth about $100,000. In the interim, we had kept our jobs, gotten raises and bonuses and, most important, had dodged a bullet that all but killed those who ran to make their instant fortunes," he wrote.

While Insana confessed to being certainly more than a little miffed that he didn't follow the lead of one of his friends who bought bitcoin at $300, he still doesn't really have faith in the controversial digital currency.

"As yet, bitcoin and other cryptos lack the three defining characteristics of money: a unit of account; a medium of exchange, and a storehouse of value," he wrote.

Bitcoin's price remains very volatile, Reuters explained.

Bitcoin held its overnight gains in early U.S. trading on Tuesday as the world’s biggest and best-known cryptocurrency rebounded on light trading volume from its worst week since 2013. The digital currency was last up almost 10 percent at $15,300.00 (£11,460) on the Luxembourg-based Bitstamp exchange. It lost nearly 30 percent at one point last Friday at $11,159.93.

To be sure, bitcoin’s rebound from a five-day rout has drawn investors back to stocks related to cryptocurrency and blockchain technology, Bloomberg reported.

Riot Blockchain Inc. jumped 20 percent, while LongFin Corp. added 38 percent. Both had fallen more than 30 percent in the past four days as bitcoin plunged from a record. The biggest cryptocurrency rose 17 percent to $16,075 as of 12:04 p.m. in New York.

Bitcoin’s more than 1,500 percent rally this year has prompted investors to snap up shares in companies often seen as a safer alternative to investing directly in the cryptocurrency itself. When the digital coin tumbled last week, the proxy stocks slumped as well.

Still, the trend that’s seen investors pour into all things crypto became a frenzy, as obscure microcap companies reoriented to focus on some aspect of the craze, resulting in astronomical stock gains sparked simply by a name change.

(Newsmax wire services contributed to this report).