Marriott International now accounts for nearly one in four hotels under construction worldwide following its acquisition of Starwood Hotels & Resorts in September 2016.
The figure was revealed by Arne Sorensen, president and chief executive of Marriott International, as the company reported its 2016 financial results.
The newly expanded hotel company, now the largest in the world, comprises 30 brands and more than 6,000 hotels.
"Together with owners and franchisees, Marriott and Starwood added more than 68,000 rooms during the year and, despite a tightening credit market, drove our pipeline of hotels under development to more than 420,000 rooms," said Sorensen.
Full year combined and adjusted EBITDA increased by 9% to $2,987 (£2,387) while revenue per available room (revpar) rose by 0.8% worldwide.
The company's debt by the end of the year had increased to $8,506m (£6,800m), up from $4,107m (£3,282) at the end of 2015.
Sorensen said that the company had "never been more optimistic about our long-term prospects", with global revpar forecast to increase by 0.5 to 2.5% during this year.
"Not including asset sales, we expect to return $1.5b to $2b (£1.2b to £1.6b) to shareholders in share repurchases and dividends in 2017," he added.