American stocks look cheapest in years. Trump's advice? 'Buy the dip'

S&P 500 at cheapest relative to forward earnings since 2013

The flip side of what’s been the third-worst month for American stocks in the postwar era is that prices are a whole lot cheaper than they were before the rout.

While it may take a strong stomach to nibble at U.S. equities, they do offer the most attractive valuations since 2013, measured by the price-to-earnings ratio for the S&P 500 Index in data compiled by Bloomberg. At little more than 13 times the coming year’s estimated earnings, American stocks are also looking less of an outlier versus other advanced markets than earlier this year.

“Relative to the stretched valuations we have seen