What were you thinking?” That is the rhetorical question Scott McNealy, CEO of SunMicrosystems, asked of investors paying a “ridiculous” ten times revenues for his stock at the height of the Dotcom Mania. The incredulity in his voice is amplified by the benefit of hindsight as McNealy gave the interview this quote was taken from in the wake of the Dotcom Bust, after his stock price had lost over 90% of its value.

Indeed, what were investors thinking 20 years ago not only paying 10 times revenues for Sun Microsystems but also paying that ridiculous multiple for 44 other stocks in the S&P 500 Index? It’s impossible to know for sure but it’s a good bet they were simply counting on the “greater fool theory” or the idea that someone will come along and pay an even more ridiculous price than they did. At some point, however, the market ran out of fools and the Nasdaq fell 83%.

It’s interesting to note that we seem to have found even more fools today than we did back then. Nearly 60 of the S&P 500 Index components currently trade more than 10 times revenues. There’s no telling when the current market will run out of fools this time but, when it’s all said and done, that last buyer may justly earn the title “greatest fool” of all time. And only with the benefit of hindsight will it really feel like the abject folly it should.