Andrew Kelly / Reuters On Monday, Marriott announced that it will buy Starwood Hotels and Resorts for $12.2 billion. Since this summer, Starwood has been in talks with various large companies—including InterContinental Hotels Group and Hyatt—regarding a potential sale. After buying Starwood, Marriott will become the biggest hotel company in the world, surpassing Hilton with more than 1 million rooms in about 5,500 hotels.