A new study by the Brookings Institution indicates that total investment in US AI data center construction is projected to reach $10.3 trillion between 2025 and 2032, averaging approximately 3.63% of GDP annually. This proportion is 1.6 times higher than the peak of the railway era and over three times that of the internet and telecom boom, signaling the largest infrastructure investment wave in history. Stijn Van Nieuwerburgh, a professor at Columbia Business School, warns that AI investments by hyperscale cloud providers such as Meta and Microsoft have exceeded their operating cash flow, leading to approximately $1.4 trillion in debt issued through off-balance-sheet financing structures like leases, joint ventures, and special purpose vehicles, with about half held by banks. He is concerned that if demand or revenue falls short of expectations, the risk could spill over into the banking system, and calls for a comparable disclosure system to track these risks.