Investors are feeling pretty good about things right now. The CNN Money Fear and Greed Index climbed into "Greed" territory on Monday, hitting 55.9 compared to its previous reading of 53.5. That shift came as U.S. stocks pushed higher, with both the S&P 500 and Dow Jones reaching fresh all-time highs.

Monday's session saw the Nasdaq Composite gain around 0.3%, closing at 23,733.90. The S&P 500 rose 0.16% to 6,977.27, while the Dow Jones climbed roughly 86 points to finish at 49,590.20. Last week was solid too—the S&P 500 gained 1%, while the Dow and Nasdaq surged 2.3% and 1.9%, respectively.

The day brought some unusual market dynamics. Gold and silver both jumped to fresh record highs as investors digested news that the Department of Justice opened a criminal probe into Federal Reserve Chair Jerome Powell over renovation costs at the Fed's headquarters. The reports sparked concerns about the central bank's independence, sending investors toward safe-haven assets even as stocks continued their climb.

Most sectors on the S&P 500 closed in positive territory. Materials, consumer staples, and industrials stocks posted the biggest gains Monday. Energy and financial stocks went the other direction though, bucking the broader market trend and closing lower.

On the earnings front, investors are watching for results from Delta Air Lines Inc. (DAL), JPMorgan Chase & Co (JPM), and Bank of New York Mellon Corp (BK) today.

Understanding the Fear and Greed Index

The Fear and Greed Index measures current market sentiment based on the idea that excessive fear drives stock prices down, while excessive greed pushes them up. The index calculates sentiment using seven equal-weighted indicators, producing a score from 0 to 100. Zero represents maximum fear, while 100 signals maximum greediness. At 55.9, Monday's reading indicates investors are leaning toward optimism without hitting euphoric levels.