That's a P/E ratio based on the past four reported quarters, over which time earnings at Nvidia increased so much that the earnings for the last reported quarte

That's a P/E ratio based on the past four reported quarters, over which time earnings at Nvidia increased so much that the earnings for the last reported quarter was over 4 times that of four quarters ago. Assuming that future earnings for the next year are consistent with the last reported quarter, they're valued at 45x earnings. But of course such a valuation still only reddit makes sense assuming growth (and the projected earnings for the next quarterly report is indeed expected to be 12% higher, giving a 40x p/e valuation). Consider that Amazon's P/E (using the last reported quarter as the baseline for the future - Amazon has had consistently increasing earnings over the last year, let's assume it doesn't decrease from here) is 43x.