In June 1932, Horch, Audi, DKW and Wanderer merged to form Auto Union A.G., which led to the creation of the four-ringed logo now seen on modern Audi automobiles. Since Horch 750 chassis no. 75450 was manufactured in 1933, it is therefore a very early car to wear this famous badge. Production numbers were small for the large Horch chassis, and a total of only 173 were made of the 8-cylinder 4.5-litre type 750.
The Offener Tourenwagen was primarily used by the highest-ranking officers. Due to their quality and reliability, these cars were used through the Second World War and many did not survive the conflict. Not so for chassis no. 75450. After the surrender of the German army, the car remained in the former Czechoslovakia. In 1945, local authorities assigned the car to the fire department in the town of Senice and later in Litovel. After 20 years, the restoration was completed in 2017, and has seen little use since. It is believed that chassis no. 75450 is the only surviving Horch 750 Offener Tourenwagen.