While Palantir has proven itself to be a great company, whether its stock is a buy is a totally different question. While great companies typically don't trade at bargain-basement prices, valuation does still matter.

Palantir (NYSE: PLTR) has been one of the hottest artificial intelligence (AI) stocks to own this year. It's up around 280% as of the time of this writing and has far exceeded many investors' expectations.

It can be so hard to convince yourself to take some profits off of your portfolio's most prominent winners. Indeed, it feels somewhat counterintuitive to trim off the top of one's top performers. And while selling some stock after a parabolic or vertical spike may prove a poor decision over the near term (or,

Palantir Technologies, the newest S&P 500 member, was the index's best performer in 2024 as of Nov. 15. But it didn't last long. Nvidia was the biggest S&P 500 leader in 2023 and ruled for much of 2024,