Bruce Duncan, chairman of the USA-based company said that financial advisors Lazard had been retained to help explore "the full range of strategic and financial alternatives" available to Starwood.
The announcement regarding a possible sale of the company was made alongside the publication of the group's first quarter results for 2015 highlighting a 27% fall in like-for-like net income to $99m (£64m). Earnings per share also dropped 19% to 58 cents (38p).
Adam Aron, interim chief executive of Starwood who stepped into the shoes of Frits van Paasschen - following his sudden departure from the company - in February, said that while the overall results were ahead of expectations, steps were being taken to increase efficiencies by "reducing costs and more smartly deploying our resources".
Starwood currently operates more than 1,200 hotels in around 100 countries. Its 10 brands include St. Regis, the Luxury Collection, W, Westin, Le Méridien, Sheraton, Four Points by Sheraton, Aloft, Element and the recently introduced Tribute Portfolio.
In the UK, Starwood's portfolio includes Aloft Liverpool; Aloft London Excel; Le Meridien Piccadilly; Sheraton Grand Hotel & Spa, Edinburgh; Sheraton Heathrow; Sheraton Skyline; Trump Turnberry, a Luxury Collection Resort; the Park Lane Hotel; the Park Tower Knightsbridge, a Luxury Collection Hotel and W London - Leicester Square.
In November 2014 the group lost the contract to manage the Lanesborough hotel in London under its luxury St Regis brand to the Oetker Collection.