Jefferies analyst Brent Thill reaffirmed a Sell rating on Palantir Technologies (PLTR, Financials), maintaining a $60 price target, citing concerns about valuation and insider selling.

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Despite Palantir's advancement in artificial intelligence, Thill said it is the most costly company Jefferies covers. The company thinks there is little upward potential for investors as the stock price already accounts for momentum connected to artificial intelligence.Insider selling was one of the main issues the paper highlighted. Recent sales of $310 million worth of Palantir shares by co-founder Stephen Cohen indicate overvaluation or management's misgivings about the company's future stock performance, according to Jefferies. Although insider sales do not always point to basic flaws, big transactions of this kind might cause investor questions about leadership credibility.Jefferies noted Palantir's artificial intelligence developments despite these misgivings. Attending the company's latest AI Platform event, Palantir showed case studies proving the platform's capacity to improve operational efficiency. Designed to enable companies to include artificial intelligence into regular operations, the AI tools were said to be interesting. But Jefferies thinks Palantir's stock price already shows these qualities.Growing investor excitement in artificial intelligence has helped Palantir gain from which its stock has surged recently. Instinctive in AI-driven data analytics and government contracts, the business has drawn attention from institutional and individual investors. Jefferies is still dubious about the value of the company, however, as it trades at a premium above rivals in the software and artificial intelligence industries.