Amazon Web Services said it has designed an in-house liquid-cooling solution for its data-centre racks after concluding that commercial offerings took up too much floor space and could not be deployed quickly enough to support new Nvidia GPUs. The In-Row Heat Exchanger, built in 11 months, will be rolled out across AWS facilities as the company deepens vertical integration in critical infrastructure. The announcement sent shares of long-time supplier Vertiv Holdings down as much as 10% to roughly $119.74 on Thursday, before paring some of the loss. Investors feared AWS could shift spending away from Vertiv’s thermal-management products, which Bloomberg Intelligence estimates account for about 10% of the company’s revenue. Several analysts argued the market reaction is excessive. Evercore ISI kept an Outperform rating and a $150 price target, saying Vertiv remains a key provider of components for AWS cooling systems. Deutsche Bank called the sell-off “overblown,” noting AWS designed but does not manufacture the hardware, while Melius Research upgraded Vertiv, contending capital-expenditure risks have eased. The debate underscores the vulnerability of specialised suppliers when hyperscale cloud operators build technology in-house, even if new systems may complement rather than replace existing facility-level cooling gear.