Palantir shares tumbled Tuesday afternoon, extending recent losses as a high-profile short seller fueled worries the stock could be overvalued after a strong run earlier this year.

Palantir shares have fallen around 15% across the last five days of trading, completely erasing gains made near the start of the month.

The S&P 500's best stock this year is fighting back, as it looks set to avoid suffering its worst stretch in 2 1/2-years. Palantir's stock was rallying 1.1% in recen

After the growth stock more than doubled this year, it has been cooling off over the past week 10 stocks we like better than Palantir Technologies › Palantir Technologies (NASDAQ: PLTR) shares have been volatile all year,

In recent days, Palantir's stock has been showing signs of slowing down. After hitting a new all-time high of $190 on Aug. 12, it has proceeded to trade lower. By Monday, the AI stock would close at just over $174 -- down 8% from its recent high.

Palantir Technologies has created one of the most dramatic stories on Wall Street this year, defying conventional investment narratives. In 2025, it became the top-performing stock in the S&P 500, surging over 106% and at points climbing 144% from the start of the year—outpacing even AI heavyweights like Nvidia.

The major indexes close the day with losses on Thursday after wavering earlier in the session. Palantir stock adds suspense.

Two hedge fund managers with a track record for market beating returns sold Nvidia and bought Palantir in the second quarter.