Palantir Technologies Inc. has experienced significant volatility in its stock price, recently dropping by 5% and trading at approximately $69.69. The company's valuation has surged to a market cap of $165 billion, with a price-to-earnings (PE) ratio reaching around 300x earnings. Notably, Shyam Sankar, Palantir's Chief Technology Officer, executed a massive insider sale of $368 million in shares, marking the largest transaction from the company in over a year. This follows a trend of insider selling amidst concerns over the company's high valuation, which has drawn criticism from investors, including Stanley Druckenmiller, who recently divested from Palantir at a PE ratio of about 200x. The stock's performance has raised questions about sustainability, especially in light of broader market movements impacting tech stocks.