auto-makers, starting with Citroën, but fairly soon followed by Peugeot and Renault (who got themselves into an acrimonious litigation with Ambi-Budd over alleged patent infringements) invested in order to establish their own press-shops. Regardless of whether the bodies came from an Ambi-Budd factory in Berlin or were stamped using presses in the manufacturer's own premises, further heavy investment was needed for the dies to make the individual panels which more often than not were different for each car model. Nevertheless, once that investment in pressing equipment had been incurred, the individual cars bodies were much quicker and cheaper to produce than the old timber framed horseless carriages. By 1928 the B10's "all-steel" bodied successor, the B12, was being produced at the rate of 400 cars per day, and accounted for 30% of the cars produced in France at the time. The challenge, not just for the auto-makers, but also for their accountants, bankers and other investors, involved record creation and paying to amortize the up-front capital cost over a series of cars that might be in production for five years or more. Provided that the burden of financing the initial capital investment could be sustained until it had been paid off through the production and sale of sufficient cars, producing cars with all-steel bodies could be very profitable, with the added bonus that France's second tier auto-makers would never be able to contemplate the capital investment necessary, so that through the later 1920s and 1930s the leading automakers in the volume sector relentlessly gained market share while smaller competitors fell by the wayside. The troubled state of Citroën's finances during the ten-year run-up to their 1935 bankruptcy, and the relative dearth of major model changes involving new bodywork, suggest that Citroën and their bankers struggled to master the cost implications of being the first auto-maker in Europe to build cars using all-steel car bodies. Citroën's survival, following its bankruptcy, under Michelin ownership, as one of the leading French car makers between 1935 and 1974 nevertheless was only possible because they were one of a handful of French automakers that adopted the "all-steel" car body technology having launched the chassis-less unibody Citroën Traction Avant. Sources and notes Book list Jacques Wolgensinger, André Citroën, Lupetti, J.P. Foucault, Le 90 ans de Citroën, Éditions Michel Lafon, AA.VV., Citroën 1919-2006 - La storia e i modelli, Editoriale Domus Type B10 Citroën Cars introduced in