The guarantee was devised such that on each return trip to the Netherlands Trading Society would guarantee a cargo of 600 lasts (c. 1,200 tons), but in total not more than 4,800 lasts in the first year. The guaranteed price would be 22,50 guilders higher than the average price agreed by the NTS for sailing ships in the previous 12 months. The minimum for this average would be 75 guilders per last, so the guaranteed price was 97.50 guilders. In case that the company would use smaller ships, this minimum would be 20 guilders above the average. For tin the tariff would be only one fourth of the above.