Berkshire bought 1,277,256 shares of the global pizza delivery chain, which were worth $550 million at the end of the quarter. Domino's shares soared on the news after hours on Thursday, which is typical when Buffett's company buys a new stock. Domino's finished the after-hours session up 7.8%.

The insurance titan released its 3rd-quarter portfolio update, revealing new buys in a pizza chain company and a pool supplies company.