Alex Crippen's Warren Buffett Watch newsletter reports Berkshire Hathaway's fourth-quarter rally reaching 19.1%, with Class A and Class B shares closing at record highs 11 and 10 times respectively since October 1, against a 1.2% S&P 500 dip. The newsletter cites CNBC's view that investors treat Berkshire as a safe haven amid AI worries, suggests continued Bank of America selling from 10-Q numbers, notes a planned $1.1 billion yen bond sale, and passes on Barron's takes that Geico trails Progressive and that Berkshire may be buying Class A stock directly to boost buybacks.