 Peoples United Financial Inc said on Monday it would buy United Financial Bancorp Inc , the holding company for United Bank, for about 743 million in stock. Shares of United Financial were up 4 at 14.58 per share in extended trading. Shareholders of United Financial will receive 0.875 shares of Peoples United stock for each share they hold, valuing the company at 14.53 on a per-share basis based on Mondays close. 