Börse Berlin AG (or Berlin Stock Exchange) is a stock exchange based in Berlin, Germany, founded in 1685 through an edict of Great Elector Friedrich Wilhelm and is one of the oldest exchanges in Germany. History The Berlin Stock Exchange was founded on June 29, 1685 in Berlin by Elector Friedrich Wilhelm. The first trading session took place on the 25th of February 1739. First, the upper floor of the former Lusthaus in the Lustgarten next to the Berlin Cathedral in direct proximity to Berliner Stadtschloss was used before this 1798 in favor of new building for the stock exchange at the same place was demolished. The bearer of the stock exchange was from 1803 the United Stock Exchange Corporation, from 1820 the newly founded corporation of merchants. The building in the Burgstraße 25–26 on the other side of the Spree was built from 1859 to 1863 by Friedrich Hitzig and opened on 1 October 1863. Because of its location in Burgstrasse, the Berlin Stock Exchange was also called "The Burgstrasse". The total cost of the construction was 700,000 Taler. Economically, until the beginning of the First World War, the Berlin Stock Exchange was one of the three most important in the world – after London and next to New York. With the general mobilization of Russia on July 30, 1914, the beginning of the First World War, it was initially completely closed. The unrestricted free market was resumed only on 2 November 1917. In 1920, when the corporation of the Kaufmannschaft merged after one hundred years of existence in the Berlin Chamber of Commerce founded in 1902, the sponsorship of the stock exchange passed on to the latter. In 1922, the Stock Index of the Statistical Office was calculated for the first time, based on the average price level of around 300 representative shares of the Berlin Stock Exchange. Wirtschaftsrundfunk, an agency for business news, had an office in the stock market. The Black Friday on 13 May 1927 caused the stock index on the stock exchange to collapse by 31.9 percent. Friday The Black Friday . In: The Time, No. 14/1967. At the end of 1926, 917 public companies were traded on the Stock Exchange, end of 1932 It was 659. By 1943, the number of listed companies dropped to 450. The Second World War in 1943 led to suspension of the price determination by the Statistical Reichsamt.