ARK’s Cathie Wood counters Bill Ackman’s inflation warning

Two of Wall Street’s loudest voices are arguing about the same question: does AI break the Federal Reserve’s playbook? Bill Ackman thinks it might, in a way that fuels inflation. Cathie Wood thinks it might too, just in the opposite direction. The ARK Invest CEO and CIO pushed back on Ackman’s warning that the Fed’s September rate hike could backfire. Her case rests on two claims: the 10-year Treasury yield sits at its long-run median, and AI inference costs are falling at a pace that makes old inflation fears look dated. How the argument unfolded It started on September 25, 2026, when Ackman posted on X about the Fed’s 25 basis point rate increase. He suggested the move may have been a mistake. Ackman’s concern is that AI spending may not respond to that brake pedal. If demand for AI resources is inelastic, meaning buyers keep paying regardless of cost, higher borrowing costs might not slow it down. In his framing, that could feed a self-perpetuating inflationary spiral. Wood replied on September 29. She argued that rising interest rates reflect genuine real yields and stronger-than-expected growth, not inflation pressure creeping into the system. The numbers behind Wood’s case Wo...