On September 13, 1921, the Swiss Social-Democratic party filed an initiative petition for an amendment to the consitution, signed by 87,535 citizens, the required number being 50,000. The amendment thus proposed provided for the levy of a tax or special assessment upon property holdings in excess of 80,000 francs, the rates on personal holdings rising from 8 per cent upon the first 50,000 francs to 60 per cent upon amounts over 3,000,000 francs. Cantons and communes were to receive each 20 per cent of the amount yielded by the tax within their borders, the remaining 60 per cent going to the federation. The purpose of the tax, as officially stated, was to enable the public authorities to meet the obligations imposed by their social policies, particularly in such matters as old age, invalidity, and other forms of social insurance.