Warren Buffett's right-hand man Charlie Munger said markets are even crazier now than during the dotcom bubble.
"I wouldn't want any one of them to marry into my family," he said about people who invest in cryptocurrencies.
The Berkshire Hathaway exec said China is right to stamp down on bubbles and take a tough line on digital assets.
Warren Buffett's deputy Charlie Munger has said markets are "even crazier" right now than they were during the dotcom bubble.
Munger blasted cryptocurrencies, and said those who invest in them are just thinking about themselves, according to the Australian Financial Review. He also labeled US millennials as "self-centered."
The 97-year-old has been Buffett's closest confidante for decades and is vice chairman of the sprawling Berkshire Hathaway conglomerate. He has a net worth of $2.2 billion, according to Forbes.
"The dotcom boom was crazier on the valuations even than we have now. But overall, I consider this era even crazier than the dotcom era," he said in a Friday interview at the Sohn Hearts & Minds Investment Conference in Australia.
"You have to pay a great deal for good companies and that reduces your future returns."
The dotcom boom was a period of breakneck growth in technology stocks. Investors poured money into companies with little in the way of revenue or profits, as excitement built up around the potential of the internet.
It ended in a huge stock-market crash in 2000, with the Nasdaq falling as much as 9% in one day, and 25% in a week.
Many investors have compared the current stock market to the dotcom bubble, pointing to companies such as Rivian. The electric-vehicle startup is yet to deliver meaningful revenue, but still went public last month. It is now worth $95 billion, making it the world's sixth-biggest carmaker by market capitalization.
Munger said China, which is cracking down on debt in the economy, was right to "step hard on booms and to not let them go too far."
The Berkshire executive is a long-running critic of cryptocurrencies, and told the conference that he wished digital assets had never been invented. "The Chinese made the correct decision, which is to just simply ban them," he said.
"Believe me, the people who are getting in cryptocurrencies are not thinking about the customer, they're thinking about themselves. Just look at them. I wouldn't want any one of them to marry into my family."
Munger said US millennials are "very peculiar: very self-centered and very leftist."
His comments came a month after Berkshire Hathaway's latest earnings revealed its cash pile hit a new high of $149.2 billion in the third quarter.
Munger said at the conference that sky-high stock prices meant finding good companies to buy was difficult.
"You want companies that have high earnings on capital and have a durable competitive advantage, and if you can add to that they've got a good management instead of a bad one, that's a big plus too," he said, according to the AFR.
"But what you'll find is that the great companies of the world have been discovered. They're very expensive to buy."
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