The analysisThe S&P 500 (^GSPC) has hit its second-most expensive valuation in history, as measured by the Shiller P/E Ratio, better known as the CAPE ratio. As it stands today, the CAPE ratio far surpasses the Crash of 1929 and is only slightly behind the levels seen during the dot-com bubble. The CAPE ratio peaked at about 44.19 in November 1999, at the height of the internet bubble, then went on to plunge to 21 by January 2003. The dividend yield on the S&P 500 measures the total annual dividend income generated by the companies in the S&P 500 index relative to the index's combined market value. Click here for in-depth analysis of the latest stock market news and events moving stock pricesRead the latest financial and business news from Yahoo Finance