In the early forties of the 20th century, Western Union has used the first time a commercial intercity microwave transmission system. Another invention of Western Union - time synchronization. In 1866, Sibley ordered the engineers to develop a Western Union telegraph system of stock quotes in real time. The size of the commission fee for the transfer is charged according to the Western Union tariffs and depends on the amount of money sent. July 3, 1884 the company's shares were included in the calculation base for the newly created stock index Dow Jones Transportation Average. In 1884 Western Union has become a joint-stock company and was brought to the stock exchange. The company has entered in the first American stock index Dow Jones. Sibley, the founder of Western Union, did not build a new telegraph lines, and persuaded the other players to join. American Telegraph Company, however, still had to buy it.