The Shiller P/E ratio passed a mark on Monday it last hit during the dot-com bubble. The stock-market indicator peaked before the S&P 500 crashed 49% in the early 2000s. AJ Bell's Russ Mould said stocks are pricey, but "you don't know when trouble is going to strike!" A trusted market gauge has surged to its highest levels since the dot-com bubble, signaling stocks are the most expensive in 25 years. The Shiller P/E ratio, also known as the cyclically adjusted price-to-earnings (CAPE) ratio, compa ...