Traders work on the floor of the New York Stock Exchange. NYSE The S&P 500 eked out a small gain Wednesday as investors evaluated their holdings following a booming first half of the year led by artificial intelligence plays. The broad market index ended the day up 8.60 points, or 0.16%, to close at 5,477.90. The Dow Jones Industrial Average added 15.64 points, or 0.04%, to end at 39,127.80. Meanwhile, the tech-heavy Nasdaq Composite added 87.50 points, or 0.49%, to finish at 17,805.16. The Nasdaq is set for a 18.6% first-half gain because of a big run in Nvidia. After trading lower for much of the day, the chipmaker closed up around 0.3%. It was a modest move after Tuesday's 7% climb. The AI chipmaker's $3.1 trillion market value has come to dominate the cap-weighted S&P 500, and its 150% surge in 2024 has sparked concerns that most other stocks are failing to participate in this year's rally. Shares of Amazon jumped 3.9%, leading the Nasdaq's up...