The record stock market gains are heavily reliant on a few large tech stocks, primarily driven by excitement around AI. Nvidia, Microsoft, Apple, and Alphabet alone added over $1.4 trillion in value this month, more than all other S&P 500 stocks combined. Nvidia, boosted by AI demand, accounted for half of this gain. While AI has spurred significant growth since the launch of ChatGPT in late 2022, concerns arise that the surge may resemble the unsustainable profit levels seen in the 2007 banking sector rather than a pure stock bubble.