Bull markets, it is said, climb a wall of worry. There are certainly plenty of reasons to worry. But markets are no longer climbing, which indicates the bull market is dead. Since markets are already highly valued, that would not be surprising.

Standard & Poor’s composite index of the US market has in effect marked time since June 2014. According to Robert Shiller’s cyclically adjusted price/earnings ratio, the US market has been significantly more highly valued than it is at present only during the disastrous bubbles that burst in 1929 and 2000. Professor Shiller’s well-known measure of value is not perfect. But it is a warning that stock market valuations are already generous and that a continued bull market might be dangerous.

Still more important, a portfolio rebalancing is under way. The most important shift is in the perceived economic and financial prospects for emerging economies. As a result, capital is now flowing out of emerging economies. These outflows are driving the strong dollar. Given that, the US Federal Reserve’s decision to tighten monetary policy looks like an important blunder.