1. Berkshire increased stakes in Chubb Ltd. by 16% this quarter. 2. Chubb shares gained 9.1%, significantly boosting Berkshire's portfolio. 3. Berkshire trails S&P 500 performance with a 9.9% gain so far. 4. Buffett's management period may end with underperformance versus S&P 500. 5. Alphabet also became a top 10 holding, aiding returns.