This is bad news for big US AI companies, because cheap Chinese rivals threaten the profits their sky-high stock values depend on.

• A Chinese company, Meituan, built an AI that competes with top US labs — showing US firms have no lock on the technology.
• On the same task, the Chinese model costs a fraction of the American one at nearly the same quality.
• The whole AI stock boom assumes US companies will eventually collect huge profits because the world has no other choice — but now there is a choice.
• You can't earn back a trillion dollars selling something a rival gives away at 90% of the quality for 10% of the price.

Outlook: If cheap competitors keep matching US models, the profit assumption holding up AI stocks could crack, pressuring those valuations.