Billionaire investor Ken Griffin is the founder and CEO of Citadel Advisors, one of the most successful hedge funds in the world. He is popular for his open-mindedness to diverse asset classes and his quantitative investing approach. His personal net worth is estimated at $51.8 billion (£38.5 billion), according to Forbes' latest estimate.
Under Griffin's leadership, Citadel has generated over $74 billion (£55 billion) in net gains since its inception in 1990. The hedge fund has outperformed the S&P 500 by 8 percentage points over the last three years.
In Q3, Griffin's hedge fund sold 1.6 million Amazon (Nasdaq: AMZN) shares and, at the same time, purchased 388,000 shares of Palantir Technologies (Nasdaq: PLTR), which has gained over 1,000% since January 2024, compared with Nvidia's (Nasdaq: NVDA) 281% gains over the same duration.
Why Did Griffin's Citadel Sell Amazon Shares
Amazon is a leader across ecommerce, digital advertising, and cloud computing. The company has been rapidly integrating AI to ramp up sales and improve earnings in recent years.
The company's investments in AI have helped the company post a 13% revenue increase in Q3 to $180 billion (£133.9 billion) as sales growth across its advertising and cloud computing divisions steadily climbed. Amazon's Q3 operating margin also jumped 60 basis points (excluding two one-time charges) while operating income rose 23% to $21.7 billion (£16.1 billion).
According to Wall Street analysts, Amazon's earnings are expected to increase 18% annually over the next three years. Its current valuation of 33 times earnings also looks reasonable. Despite such tailwinds and robust financial performance, Griffin still chose to sell Amazon shares last quarter. His investment decision could be simply a profit-taking move, and it is unlikely he has lost confidence in the company.
Griffin Buys Palantir Despite Extreme Valuations
Palantir develops data analytics and AI for clients in the public and private sectors. The company's differentiated ontology-based software ensures that solutions are designed using a decisioning framework, which has become more impactful over time through machine learning models, with use cases spanning supply chain management, inventory optimization, financial fraud detection, and battlefield insights.
In 2025, Forrester Research analysts recognised Palantir as the most capable AI/ML platform on the market, even placing it above Alphabet's Google, Amazon Web Services, and Microsoft Azure. This year, Forrester Research ranked the company as a leader in AI decisioning platforms, likely based on the company's innovations and robust financial results.
In Q3, Palantir's revenue rose 63% to $1.1 billion (£818.6 million) and adjusted earnings more than doubled to $0.21 (£0.16) per diluted share, primarily attributable to growing demand for its AI platforms.
However, the issue is with the stock valuations, with shares trading at 119 times sales, making it the most costly stock in the entire S&P 500 index. Note that Palantir's stock price has jumped 11 times since January 2024, but revenue has increased less than twofold, meaning that the main reason the stock price gained is that investors are continuing to pay higher price-to-sales multiples.
This trend is unsustainable over time, and the valuation will matter at some point, when the stock may face significant corrections.
Disclaimer: Our digital media content is for informational purposes only and does not constitute investment advice. Please conduct your own analysis or seek professional advice before investing. Remember, investments are subject to market risks, and past performance does not guarantee future returns.
