The concentration of the U.S. stock market has reached a record level, with the top 10% of the largest stocks now accounting for 75% of the market. This surpasses the previous high seen before the Great Depression and the 73% share recorded at the peak of the 2000 Dot-Com Bubble. The Nasdaq 100 index, adjusted for the U.S. M2 Money Supply, has also hit a record ratio of 0.97, which has doubled over the past five years, reflecting a significant increase in technology stock prices. Analysts are drawing parallels between the current situation and past market bubbles, particularly citing NVIDIA's position in the market and comparing it to Cisco's experience during the Dot-Com Bubble, when Cisco was the most valuable company and subsequently saw its stock decline by over 80% after the bubble burst. NVIDIA's history of resilience through crises, including a critical moment in the 1990s when it had only nine months of cash left, is highlighted as a factor in its current standing in the market.