Lots of people think the market is dangerously expensive. They take a look at the S&P 500 graph, which looks like this:
And they’ll point out that we’re now about 50% higher than we were in 2007, just before the last crash. Has there been a stupendous improvement in the real economy since then? No, they’ll argue, and so the index level must have been frothed up. You’ll probably hear something about printing money at this point.
But the graph in itself doesn’t tell us a great deal, since it’s raw data without any comparator. Much better to look at how the companies making up the index are doing, and how they are valued in aggregate relative to a proper measure, like earnings. At this point the Shiller PE graph often gets trotted out. It is basically a ‘normalised’ price-to-earnings graph, which shows the current multiple you’re paying for the average last-10-years earnings for the companies making up the index.