U.S. stocks slipped at the start of what promises to be a busy earnings week, with major indices retreating from recent highs as investors shifted focus to corporate results. The S&P 500 and Nasdaq both dipped in early trading, reflecting caution among market participants ahead of heavy reporting season. Energy shares provided a rare bright spot as oil prices climbed.

Oil rallied amid reports that peace talks between Russia and Ukraine had stalled, raising concerns about prolonged supply disruptions. Brent crude rose over 2% to trade above $75 per barrel, lifting energy stocks even as the broader market weakened. The commodity's gain underscored ongoing geopolitical tensions weighing on global markets.

The earnings season kicks into high gear this week, with dozens of S&P 500 companies scheduled to report results. Major banks are among the first big names releasing quarterly figures, giving investors an early read on the health of the financial sector and the broader economy.