It has been a rough week for Nvidia – the chip giant powering the AI revolution and just about every American's 401(k) – and it's not just recent headlines that are threatening the stock, On The Money has learned. OpenAI Sam Altman helped spark a selloff in shares with his talk of "overexcited" investors and an artificial intelligence "bubble" – even as his company raised from investors $6 billion for a staggering $500 billion valuation. This week, short sellers reaped more than $5.6 billion betting against ...