At least the dot-com bubble was based on a real thing, the idea the Internet would transform the economy. This is just market manipulation, albeit by large groups of people acting collectively, to **** over short sellers, who're never very popular.
Yes and no. A lot of stocks of companies with real businesses like Amazon, Microsoft, Cisco went ballistic during the dot-com bubble and ran up to levels that it would more than a decade for them to reach again. But for every real company that got swept up in the euphoria there were a handful pets.coms and Webvans that never earned a penny and just lived on Alan Greenspan's genius. ... until they went bankrupt.
This is similar in that we are in a world of zombie companies that are drowning in debt, losing money, and are able to keep borrowing to stay alive. There are plenty of good companies now, too, where just like during the dot-com bubble, they are trading at the most expensive valuations in history, too. Think Apple -- great company, way overvalued. Or Alphabet. Or Facebook. They are real things. ... at the same time, there are a lot of companies that don't earn a penny and just keep borrowing or tapping the secondary IPO markets, trading at huge multiples.
It's the same exact thing in that regard. I won't bug everyone with too long of a long post, but if you want to see another symptom read up on what is going on with SPACs right now -- special purpose acquisition companies and the number of IPOs there have been in that space and how much the prices are running up.
We have been in a euphoric, mispriced environment since the financial crisis. But with what central banks have done over the last year, it is now getting into territory we have never seen before. If you buy the stock of one of those SPACs, you are just gambling. There is no business. It's just, "Give us money and value us at a ridiculous valuation. ... and trust us to reinvest it in places that will justify the insane valuation."