NSU had sold its Heilbronn factory (near the river Neckar) in 1929 to Fiat due to the economic crisis. Fiat started to produce under license Fiat Topolinos and Balillas in this factory under the brand NSU-Fiat (at the same time, the same cars were produced under license in France by SIMCA-Fiat).
In 1957, NSU decided to restart the production of personnel cars, and asked to this Fiat licensee to change its name, and therefore NSU-Fiat became Neckar. Neckar was producing less than 25,000 vehicles a year, Fiat 500 (Neckar Weinsberg), 600 (Neckar Jagst) and 1100 (Neckar Europa) slightly modified, often more luxurious and sporty than the Fiat produced in Turin.
The launch of the Fiat 1500 in 1961 and of the Neckar Panorama (derived from the Autobianchi Panoramica) allowed Neckar to reach a yearly production of 50,000 units in 1962. A nice coupe derived from the 1500 and called the Neckar Mistral was designed. A coupe and a convertible based on the Fiat 600 was produced as the Neckar Riviera. The Fiat 850 (as the Neckar Adria) was the last model produced by Neckar.
The high cost of the German workforce (compared to the Italian one) doomed Neckar. Fiat refused to sell the license of the new Fiat 124, 125 and 128 to Neckar. Production of Neckar slowed down from 1963. 50,000 cars were produced in 1962, down to 44,000 units in 1963, 22,000 in 1964, 18,000 in 1967 and 12,000 in 1970. Neckar closed in 1971 having produced 370,000 cars in total.