"It's called exhaustion in market terminology," says Fred Hickey, who is the long-time editor of the widely followed newsletter, The High-Tech Strategist.
says the same was true in the run up to the financial crisis.
Compare stocks to corporate sales or earnings, and it was clear that the market was overvalued in October 2007.
And earlier this year, the prices of technology stocks, when you factor in their current growth projections, were trading at higher multiple of earnings than they were back in 2000.
"Why anyone would expect anything other than a decline is beyond me," says Hickey