A dramatic turnaround in technology stocks has powered a $3.5 trillion increase in the Nasdaq 100's market capitalization in just four days, driven by strong earnings that have emboldened investors about the AI outlook.

The rally reflects renewed confidence following better-than-expected quarterly results from major tech companies. Investors are betting that robust corporate profits, particularly those tied to artificial intelligence initiatives, will sustain long-term growth. This optimism has translated into a broad-based surge across the index.

Market participants noted that the recent performance signals a shift in sentiment after months of volatility. The concentration of gains among large-cap technology names has lifted overall market valuations. Analysts suggest that the current momentum may continue if earnings remain supportive and macroeconomic conditions stabilize.

Bloomberg Markets reported that the speed and magnitude of the rally underscores how quickly investor psychology can change. The $3.5 trillion gain represents one of the largest four-day increases in the index's history, highlighting the pivotal role of tech earnings in shaping market direction.