Wall Street is slipping on the final day of trading for 2025, a banner year for markets that was driven by both optimism and uncertainty. The S&P 500 was down 0.3% in afternoon trading Wednesday. The Dow Jones Industrial Average slipped 159 points, or 0.3%. The Nasdaq composite was down 0.3%. Trading is expected to be light ahead of the New Year’s Day holiday, when markets will be closed. The S&P 500 is up about 17% this year as investors embraced the optimism surrounding artificial intelligence and its potential for boosting profits. Treasury yields rose in the bond market.