Americans are displaying significant optimism towards the stock market, with major indexes reaching new highs. The S&P 500 has risen by 18% this year, and U.S. households' stock allocations have climbed to around 42% of their total financial assets, the highest level since 1952, according to JPMorgan. Fidelity Investments reports an increase in the number of 401(k) accounts worth at least $1 million. This surge in the stock market has contributed to a rise in Americans' net worth, with many becoming millionaires. Investors are becoming increasingly bullish on stocks, with market euphoria at an all-time high.