In 2024, the stock market is off to a roaring start, with the S & P 500 boasting a 15% year-to-date total return, making it the 21st best run through June since 1900, according to Goldman Sachs. Historically, when the index has been up at least that much at this point, the rest of the year is up 72% of the time, with a median further gain of almost 9%. Investors are reaping huge rewards with a 12-month Sharpe ratio triple the long-term average, pointing to an extraordinary risk-reward proposition. However, concerns loom about the market's dependency on a handful of massive companies for its gains, suggesting a potential vulnerability. Market conditions remain positive, but nuances like the recent stumble in high-momentum stocks and potential implications of structural and mechanical influences underscore the need for vigilance amidst the seemingly smooth sailing.