Are we in a tech stock market bubble? I’m amazed to be asking that question, given we are still in the grips of the deepest economic downturn since the Great Depression. But tech stocks have risen so far and fast in the past year, despite a brief recession-related dip, that parallels to the 2000s are hard to escape. The top dozen tech stocks have risen 170% on average in the past year, versus 146% in the year before the 2000 crash. And the top ten tech stocks comprise an outsized 29% of the S&P 500 today, compared to an outsized 23% in 2000.