1. Todd Combs leaves GEICO and Berkshire Hathaway to join JPMorgan. 2. He will lead JPMorgan's $10 billion Security and Resiliency Initiative. 3. Combs' departure could affect Berkshire's insurance operations. 4. His investment management experience was critical for BRK-A's strategy. 5. Market may view this as a leadership gap at Berkshire.