Nvidia's flood of giant AI financing deals is raising fears of a bubble, which is bad news for investors if the money ever stops flowing.

• Nvidia is making huge deals — including guaranteeing up to $250 billion so OpenAI can lease data centers — where it invests in companies that then use the cash to buy Nvidia chips.
• Critics call this "circular financing": money loops between Nvidia, OpenAI, Oracle, xAI and others, making profits hard to trust.
• Many AI companies burn cash and survive only by borrowing, so if the Fed raises rates or oil-driven inflation lifts borrowing costs, their business models are at risk.
• China is a wildcard — chipmaker CXMT soared on its debut, and cheaper Chinese AI models could undercut the pricey US ones from OpenAI and Anthropic.
• There's doubt about real-world payoff, with much AI use so far being novelty videos rather than big productivity gains.

Outlook: Expect more mega-deals and heavy AI spending from Google, Tesla and others, but rising borrowing costs or weak profits could pop the bubble.