Ken Griffin of Citadel Advisors holds the record for the highest net gains among hedge fund managers in the United States. Additionally, Citadel outperformed the S&P 500 ( ^GSPC 0.49%) by 9% over the past three years, making his investment choices a valuable reference for individual investors.
In the second quarter, Griffin executed several significant trades. He reduced his holdings in Tesla ( TSLA 2.27%) for a fourth consecutive quarter, cutting the already modest position by 30%. At the same time, he dramatically increased his stake in Nvidia ( NVDA 0.34%), boosting it by 900%, making it his portfolio's second largest holding.
Notably, since the artificial intelligence (AI) surge began in January 2023, Nvidia shares have soared 1,100%. Griffin, however, had been steadily reducing his Nvidia investment, selling in seven of the previous eight quarters before making a major purchase in Q2 of 2025. Citadel’s current position in Nvidia is the largest it’s been since 2022, indicating Griffin may have sold off too soon and has since adjusted his strategy.
Here are the key details investors need to know.
Image source: Getty Images.
Tesla: The company Ken Griffin reduced in the second quarter
Tesla’s electric vehicle operations are currently facing headwinds. The company’s automotive sales have dropped for three consecutive quarters, challenged by intensifying competition, higher interest rates, and reputational issues linked to CEO Elon Musk’s political involvement. Over the past year, Tesla's market share fell by more than 3 percentage points as Chinese automaker BYD overtook it as the global leader in electric vehicle sales.
Despite these challenges, Tesla has a major prospect in the autonomous driving sector. The company recently launched its first commercial robotaxi service in Texas and is currently piloting vehicles in California, with newly granted approval to test in Nevada. Morgan Stanley analyst Adam Jonas predicts that robotaxi revenue could hit $84 billion by 2035.
It’s also worth noting that Tesla is currently behind Alphabet’s Waymo in the autonomous ride-sharing market -- Waymo already operates commercial services in five U.S. cities -- but Tesla may have a competitive advantage. Unlike Waymo, which depends on expensive sensors and detailed city mapping, Tesla uses computer vision alone, making it a more affordable and scalable solution.
Additionally, Tesla is working on an autonomous humanoid robot named Optimus. Elon Musk has stated that this project could eventually represent up to 80% of Tesla’s value, declaring during a recent analyst call that “Optimus has the potential to be north of $10 trillion in revenue.” Tesla aims to produce at least one million units per year within five years.
Currently, Tesla is trading at 170 times projected 2026 earnings, positioning it as the third priciest stock in the S&P 500. Frankly, if Tesla cannot fulfill its ambitions in robotaxis and autonomous robots, its valuation appears highly inflated. However, if the company succeeds, today’s price may look justified in retrospect. Investors must decide which outcome they believe is more plausible.
Nvidia: The company Ken Griffin added in the second quarter
Nvidia leads the data center graphics processing unit (GPU) market, with its chips -- frequently called artificial intelligence (AI) accelerators -- powering complex tasks such as AI training and inference. At present, Nvidia commands more than 80% of the market, and many analysts anticipate the company will retain this dominant position for years to come.
Nvidia’s dominance is not just due to the superior performance of its chips compared to rivals, but also because it pairs its GPUs with related networking equipment, central processing units (CPUs), and a suite of software tools that facilitate the creation of diverse AI applications.
Blayne Curtis of Jefferies noted this competitive edge in a client communication last year, stating, “Nvidia maintains control over both hardware and software aspects of the ecosystem, and its rapid release of new chip generations should only strengthen its lead.” Recently, Nvidia began shipping its Blackwell series GPUs, and its next generation, Rubin, is set for release next year.
Looking forward, Nvidia is in a strong position to continue its growth. CEO Jensen Huang expects annual spending on AI data centers to reach between $3 trillion and $4 trillion by the end of this decade, up from roughly $600 billion today. This suggests the company’s addressable market could expand by at least 400% over the next five years, supporting annual revenue growth in the upper 30% range.
Wall Street projects that Nvidia’s earnings will rise by about 36% annually over the next three years. This makes its current price -- 50 times earnings -- appear quite reasonable. Long-term investors with an outlook of three years or more may find this semiconductor company an attractive buy today.
