Société Générale was nationalised in 1945. It now had a single shareholder: the State.

The period from 1945 to 1958 was characterised in France by rapid economic recovery but also a greater disequilibrium in the balance of payments, calling for continued exchange controls and virtually permanent credit control measures. It was not until 1959 that the economy really recovered, but credit controls were reinforced due to persistent inflationary pressures.

Sharp growth in production and foreign trade opened up new areas of business for the banks. The industry underwent some quite radical changes, one of the most striking of which was much greater specialisation of credit. The range of banking services on offer expanded uninterruptedly.

Thanks to its presence in New York, Société Générale was able to take advantage of the flow of business generated by the Marshall Plan.

Société Générale continued to expand in France and elsewhere. It moved into Italy and Mexico and altered the status of its establishments in Africa after decolonisation, in accordance with the laws passed by these newly independent countries.