Expanding quickly overseas, the Marconi Wireless Telegraph Company of the UK  chartered the Marconi Wireless Company of America (MWTCA) in the state of New Jersey in 1899.  The company's early priority was to create wireless capabilities for ships at sea to communicate with each other and with shore  stations.. David Sarnoff (1891-1971), future RCA executive,began his career in electronics working for the Marconi Wireless Telegraph Company of America in 1906 at the age of 15

During World War I, the U.S. Navy seized control of almost all MWTCA assets for transmitting and receiving, leaving only their manufacturing capabilities outside wartime control. In the aftermath of World War I, when the Navy relinquished control of MWTCA, the importance of wireless technology was abundantly clear. However, the United States realized they had no domestic wireless companies and the controlling stock in MWTCA was British. Seeking to safeguard America’s ability to communicate wirelessly and securely with any nation, Admiral William H.G. Bullard contacted Owen D. Young at General Electric and arranged for the creation of an American controlled company to buy out MWTCA. The transfer included around 1,300 engineering and technical drawings from the Marconi Wireless Telegraph Company of America . Subjects ranged from circuit diagrams, wiring layouts and switchboard schematics to architectural plans for aerial towers and carrying case designs.

This new company, The Radio Corporation of America, assumed control of all intellectual, materia ,and operating rights of the former MWTCA in 1919, and was granted use of crucial G.E. licenses, most important being the Alexanderson alternator. American Marconi was dissolved as a corporation in April 1920.

Marconi Company organizational tree.
A detiled look at the history of American Marconi  can be found here.
 

This is an American Marconi stock certificate from 1913. Download image to enlarge. (Image via E-bay).

 
Credits or Reference:

 1 http://dla.library.upenn.edu/cocoon/dla/pacscl/ead.pdf?id=PACSCL_HML_246483