There have been few better stocks to own over the past three months than Palantir ( PLTR 1.42%). The stock more than doubled in that time, far outperforming both indexes and other market leaders. This performance can be traced to several events, notably Palantir's inclusion in the S&P 500 in September and its blowout Q3 earnings.

The stock market broadly has been rising faster than corporate profits, which raises the volume on criticism from skeptics that it’s gotten too expensive. The S&P 500 is still up nearly 25% for the year so far,