The U.S. market is top-heavy, with Nvidia occupying a bigger weight than any company in modern history. Risks abound, our columnist says.

Nvidia's stock price slipped Thursday, but a wave of analyst upgrades highlights confidence in its AI growth prospects.

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When Nvidia, the chip producer, reports earnings next week, investors expect the S&P 500 to have a bigger reaction than when the Fed chair delivers a big speech on Friday.

After Nvidia reports its second-quarter earnings this week, investors should keep a keen eye on another important AI chip stock.

Nvidia has grown, swelling to a $4 trillion valuation last month, so has its weighting in the S&P 500. It now makes up almost 8 per cent of the index.

Nvidia Corporation (NASDAQ:NVDA) is one of the best data center stocks to buy now, and the top stock in this list.

This AI infrastructure play has delivered bigger gains than its larger peers since going public earlier this year.

The nuance here is that the dot-com bubble was defined by abundance — too many companies, too much capital, and too many competing investment ideas. Meanwhile AI, at least so far, offers a story of scarcity built almost entirely on a single company.