US stock index futures fell sharply Wednesday evening as Nvidia capped its post-earnings rally despite strong quarterly results. Nvidia shares reversed course after a brief post-earnings surge, closing lower as investors reacted to the company's comments about inventory levels. The tech giant reported revenue and profit exceeding estimates for the January-March period but warned of supply-demand equilibrium, reducing near-term upside expectations.

Salesforce also disappointed investors, sliding 4.6% after forecasting softer fiscal 2027 revenue. While both companies posted solid earnings, their cautious outlooks signaled lingering uncertainty in the enterprise software sector. Geopolitical risks resurfaced as markets eyed potential nuclear talks between the U.S. and Iran in Geneva, with traders anticipating possible volatility before Thursday's discussions.

The market's reaction highlights how earnings guidance can override strong results, with investors now focusing on inventory management and geopolitical developments over immediate growth prospects.