India, Aug. 26 -- Global capital markets have committed an unprecedented volume of capital to AI infrastructure since 2023, intensifying through 2025-26 and drawing comparisons to railway mania and the dot-com telecom overbuild. Cumulative 2022-26 investment estimates range from roughly $1.8 trillion (Goldman Sachs) to $2.5-2.6 trillion in total 2026 AI spending (Gartner), with infrastructure alone accounting for around $1.4 trillion. The four largest hyperscalers - Amazon, Alphabet, Microsoft and Meta - are guiding towards roughly $725 billion in combined 2026 capex, up 77 per cent year-on-year; including Oracle, the group approaches $800 billion. Goldman projects hyperscaler capex could reach $5.3 trillion between 2025 and 2030. Capital...