ARLINGTON, VA— Interstate Hotels & Resorts has boosted its management portfolio by signing an agreement to manage 54 hotels currently owned by affiliates of Sunstone Hotel Investors LLC. The management of the privately-held hotel ownership group, based in San Clemente, CA, will transfer to Interstate, but will remain at their existing offices and will continue to oversee management of the hotels. The 54 properties, with 12,643 rooms and located in 16 states, are primarily premium-branded full-service properties, which include such brands as Marriott, InterContinental and Hilton hotels. The transaction will close, and is contingent on, the concurrent completion of an initial public offering by Sunstone Hotel Investors, which is currently in registration with the Securities and Exchange Commission. Sunstone Hotel Investors will be a REIT, which require s that its owned properties be managed by third-party operators. Concurrent with the IPO, Interstate will enter into new long-term management contracts with the hotels.