Question: Where is the headquarters for the Ustream company partner that is currently owned by William Morris Endeavor and Silver Lake Partners?

Context paragraphs:
William Morris Endeavor: William Morris Endeavor Entertainment, LLC, also known as William Morris Endeavor, WME or WME-IMG, is an American talent agency with offices in Beverly Hills, California, United States.  The company was founded in April 2009, after the merger of the William Morris Agency and the Endeavor Agency.  WME represents artists across all media platforms, specifically movies, television, music, theatre, digital and publishing.  It also represents the NFL and NHL.  WME also owns the Ultimate Fighting Championship and Miss Universe.  The company is run by Co-CEOs Ari Emanuel and Patrick Whitesell.

IMG (company): IMG, originally known as the International Management Group, is a global sports, other events and talent management company headquartered in New York City.  It has been owned by William Morris Endeavor and Silver Lake Partners since 2013.  Trans World International (TWI) is the event company of IMG.

Mercedes-Benz Fashion Week Miami: Mercedes-Benz Fashion Week Miami is an annual fashion week held in Miami, Florida, United States.  Mercedes-Benz Fashion Week Miami, not to be confused with Miami Fashion Week, is held every year during the Summer at the Raleigh Hotel at 1775 Collins Avenue in South Beach, Miami Beach.  Mercedes-Benz Fashion Week Miami works together with New York Fashion Week, and is the country's largest, and most important fashion week for swimwear.  IMG whom first brought its runway event to South Beach in 2004, had an ongoing partnership with Mercedes-Benz.  However, due to changes in ownership, as IMG was acquired by William Morris Endeavor and Silver Lake Partners in a $2.2 billion deal, the agency lost Mercedes-Benz as a title sponsor.  The show was cancelled for 2015 but will resume in 2016 after re-branding the popular event.

Dan Aloni: Daniel Aaron (Dan) Aloni (born August 19, 1964) is an American talent agent at William Morris Endeavor (WME), an entertainment and media agency, where he is a Partner and member of the Leadership Committee.  He was previously a Partner at Creative Artists Agency (CAA) and United Talent Agency (UTA).

Ustream: Ustream is an American live video streaming and video hosting company.  It is based in San Francisco and has more than 180 employees in their San Francisco, Los Angeles, and Budapest offices.  Company partners include Panasonic, Samsung, Logitech, CBS News, PBS NewsHour, Viacom, and IMG Media.  It received $11.1 million in Series A funding for new product development from DCM (Doll Capital Management) and investors Labrador Ventures and Band of Angels.  It is owned by an American company of the same name, Ustream, Inc., based in San Francisco, California.  Ustream was one of the live game streaming services for Sony's PlayStation 4.

Motown Motion Picture Studios: Motown Motion Picture Studios (now known as Michigan Motion Picture Studios and formerly Raleigh Michigan Studios) is located in the Detroit suburb of Pontiac and owned by Motown Motion Pictures LLC .  Motown Motion Pictures is owned by Linden Nelson, A. Alfred Taubman and John Rakolta Jr., William Morris Endeavor Entertainment and Raleigh Entertainment (10%).

Endeavor Talent Agency: The Endeavor Talent Agency was a Beverly Hills-based talent agency founded by Ari Emanuel, Rick Rosen, Tom Strickler, and David Greenblatt.  It was launched in March 1995 and went on to represent a wide variety of acclaimed film and television stars.  In April 2009, Emanuel and Endeavor executive Patrick Whitesell orchestrated a merger with The William Morris Agency, resulting in William Morris Endeavor.

Silver Lake Partners: Silver Lake is an American private equity firm focused on leveraged buyout and growth capital investments in technology, technology-enabled and related industries.  Founded in 1999, the firm is one of the largest technology investors in the world.  Notable among its investment holdings are Broadcom, Dell, Alibaba, GoDaddy, William Morris Endeavor, IMG Worldwide, Avaya, Sabre Holdings, Skype, Symantec, GLG, Seagate Technology and NASDAQ.  Silver Lake is headquartered in Menlo Park with offices in San Mateo, Cupertino, New York, London, Hong Kong, Shanghai and Tokyo.

John Fogelman: John Michael Fogelman (born c. 1965) is an American entrepreneur.  He is the CEO of FactoryMade Ventures, an entertainment and media incubator.  Formerly Executive Vice President and Head of the Motion Picture Department and the Intellectual Property Group at the William Morris Agency (WMA), Fogelman was a principal architect of the merger between William Morris and Endeavor Talent Agency, and served as a founding board member and an agent after the companies merged in 2009.  He left William Morris Endeavor in 2011 to found FactoryMade.

Robert Newman (agent): Robert Newman is a notorious Hollywood talent agent.  He is also one of the co-founder and lead of the talent agency Endeavor before it merged with William Morris and became William Morris Endeavor.

Supporting paragraphs: Ustream IMG (company)
Answer: New York City