Elon Musk, Jeff Bezos, Mark Zuckerberg, Jensen Huang, and Michael Dell saw their combined net worth drop by $26 billion in a single day on Thursday, according to the Bloomberg Billionaires Index. The sharp decline was driven by steep falls in the stock prices of their respective companies—Tesla, Meta, Amazon, Nvidia, and Dell—amid growing investor concerns over the escalating costs of building AI infrastructure and uncertainty about the financial returns from those investments. Tesla, Meta, Amazon, and Nvidia all saw their shares fall by about 2% on Thursday. The sell-off reflected broader market anxiety about the sustainability of massive capital expenditures in the AI race, especially as companies race to deploy cutting-edge hardware and data centers. Dell’s shares plunged 9% after Lenovo issued a warning about a shortage of memory chips, which is increasing production costs across the hardware sector. The news triggered fears that other tech manufacturers could face similar profit pressures. As a result, Michael Dell’s personal wealth dropped by $5 billion, bringing his net worth down to $135 billion. Elon Musk suffered the steepest individual loss, with $8 billion erased from his fortune. Despite the drop, Musk remains up roughly $57 billion this year, driven by surging valuations of SpaceX and xAI, his artificial intelligence venture. Mark Zuckerberg’s net worth declined by nearly $7 billion, adding to a year-to-date loss of over $3 billion, bringing his total to $230 billion. Jeff Bezos saw his wealth shrink by $4 billion, extending his year-to-date decline to about $27 billion. Nvidia CEO Jensen Huang lost $2.5 billion in personal wealth as the chipmaker’s stock dipped. Alphabet co-founders Larry Page and Sergey Brin each lost about $1.5 billion as Google’s parent company saw its shares dip slightly below 1%. Meanwhile, Walmart shares rose nearly 4% to a record high, buoyed by easing concerns over tariffs and a shift in investor sentiment away from overvalued tech stocks. The rally added more than $4 billion to the net worths of Sam Walton’s three surviving children—Jim, Rob, and Alice—each of whom now has a fortune exceeding $150 billion. They are among the top performers in wealth growth this year, with gains surpassing $20 billion each. The world’s 10 richest individuals collectively added nearly $600 billion to their wealth in 2023, pushing their combined net worth above $2.5 trillion—more than the current market value of Amazon.