Palantir (PLTR) has been one of the hottest S&P 500 Index ($SPX) stocks over the past year, rising 378%. Moreover, it has more than doubled so far in 2025. However, the stock has recently come under pressure,

Then, short seller Andrew Left of Citron Research said PLTR stock was "detached from fundamentals and analysis". He's certainly not the first one to suggest that the Palantir rally has gone too far. However,

Citron Research says Palantir stock at $40 per share would still be an expensive AI stock to own. Wall Street recommends caution on PLTR shares as well.