Macro pressures raise concerns over an AI investment bubble. Rising bond yields make AI infrastructure spending riskier. Analysts project the AI bubble may burst by 2027 or 2028. Heavy capital is flowing into resource-intensive frontier models. Circular financing among Big Tech adds to the risk. Concentration worries cloud the AI infrastructure roll-out. Persistent inflation and heavy government debt issuance drive bond yields higher. The midterms and ongoing war may test who can sustain AI spending.