Citadel CEO Ken Griffin significantly increased his firm's investments in AI and tech stocks during the third quarter of 2025, as revealed in the latest 13F filing. Griffin notably expanded Citadel's holdings in Microsoft, acquiring 1.99 million shares valued at $1.03 billion, and Meta, with 1.95 million shares worth $1.43 billion. Additionally, Citadel increased its stake in Apple by $652 million, adding 2.56 million shares. The investment strategy also included larger positions in Tesla, Alphabet, and NVIDIA, while reducing Amazon holdings by 39%. Griffin's portfolio adjustments reflect a strategic focus on emerging technologies, with smaller investments in quantum computing companies Rigetti and D-Wave, as well as biotech firm Summit Therapeutics. This aligns with current trends in AI and crypto markets.