In the early forties of the 20th century, Western Union has used the first time a commercial intercity microwave transmission system. In the 30's of the twentieth century, Western Union has become the world's largest telegraph company. In 1877, starting from September, New York City residents began to have the opportunity to check the time on clock with the "time ball", located on the roof of constructed in the same year a new corporate headquarters - Western Union Building. In October 2006 the company made an initial public offering of shares on the New York Stock Exchange, becoming independent from First Data company. Thanks to cooperation with Western Union the Associated Press at the end of the XIX century took almost monopolistic position in the U.S. market news.