昨夜，大涨！原因找到了

Core Viewpoint - The investment actions of Warren Buffett have significantly influenced the stock market, particularly driving the Dow Jones Industrial Average higher, while other indices like the S&P 500 and Nasdaq experienced declines [2][3]. Group 1: Market Performance - On August 15, the Dow Jones increased by 0.08%, while the S&P 500 and Nasdaq fell by 0.29% and 0.4% respectively. For the week, the Dow rose by 1.74%, the S&P 500 by 0.94%, and the Nasdaq by 0.81%, with both the Dow and S&P 500 reaching intraday historical highs [4]. - The stock of UnitedHealth surged by 12.03% to $304.16 per share, following news of Buffett's investment, marking its largest intraday gain since 2008 [6]. Group 2: Buffett's Investment Actions - According to the latest 13F report, Berkshire Hathaway, led by Buffett, established a new position in UnitedHealth, acquiring over 5 million shares valued at approximately $1.57 billion as of June 30. This marks Berkshire's re-entry into the healthcare insurance sector after a 14-year absence [8]. - In addition to acquiring UnitedHealth, Berkshire reduced its holdings in Apple by 20 million shares and in Bank of America by 26.31 million shares, while increasing its stake in Chevron by over 3.45 million shares and completely exiting T-Mobile US [8]. Group 3: Sector Performance - Major technology stocks showed mixed results, with Intel rising about 3%, while Tesla fell over 1%. The Nasdaq Golden Dragon China Index increased by 0.74%, with notable gains from stocks like Xunlei, which rose over 26% [9]. - Precious metals and oil prices collectively declined, with gold falling to $3,335.28 per ounce, down 1.86% for the week, and Brent crude oil settling at $66.14 per barrel, down 0.68% [11][13].