Alphabet (GOOG.US, GOOGL.US) saw its stock price surge nearly 10% on Thursday, closing at $384.8. The company's market capitalization increased by approximately $421 billion in a single day, marking the second-largest single-day market value gain in history, only surpassed by the roughly $440 billion gain recorded by NVIDIA (NVDA.US) a year ago driven by favorable policies. This rally was primarily fueled by the company's latest quarterly results significantly exceeding market expectations. The earnings report indicated strong demand for Alphabet's cloud computing and artificial intelligence businesses, which is widely viewed as a key signal that the company's substantial AI investments are beginning to yield returns. Following the stock price increase, Alphabet's year-to-date gain has reached 23%, with its market value rising by over $860 billion. Its total market capitalization has climbed to approximately $4.65 trillion, nearing NVIDIA's market cap of around $4.85 trillion, thereby narrowing the gap with the world's most valuable company. During this earnings season, Alphabet has emerged as one of the standout performers among tech giants. Analysts pointed out that the robust demand for its cloud and AI-related businesses validates the rationale behind its previous significant capital expenditures and has also bolstered market confidence in its AI competitiveness. In contrast, the performance of other major tech companies was notably mixed. Microsoft (MSFT.US) saw its stock price decline by 3.93% after reporting earnings; Meta Platforms (META.US) dropped 8.55% due to investor concerns over increased capital expenditures; while Amazon.com (AMZN.US) experienced only a modest gain of 0.77%.