Citigroup has raised its forecast for AI-related infrastructure spending by tech giants to surpass $2.8 trillion through 2029, from $2.3 trillion estimated earlier, citing aggressive early investments by hyperscalers and growing enterprise appetite. The Wall Street brokerage sees AI capex across hyperscalers to reach $490 billion by the end of 2026, up from its earlier estimate of $420 billion. The brokerage said big tech firms are no longer relying only on profits to fund AI infrastructure. This shift is already showing up in their financials, with spending starting to eat into free cash flows. Investors are now asking how the tech companies will fund this scale of investment, especially as traditional models fall short.