Charles E. Wilson, the president of General Electric Corporation, was so happy about the wartime situation that he suggested a continuing alliance between business and the military for "a permanent war economy."
J. P. Morgan Jr. and partner Thomas Lamont helped hatch the Dawes and Young Plans which restructured Germany's war reparations in World War I into a debt repayment plan. Owen Young, who headed the committee that presented the plan which bears his name, was the founder of RCA, the dominant electronics and communications firm in the U.S. for five decades. "As a result, in 1929, German industry was in second place in the world, but it was largely in the hands of America’s leading financial-industrial groups."
Fritz Thyssen took over the Thyssen steelmaking companies in 1926 and then formed the United Steelworks, which controlled more than 75% of Germany's iron ore reserves. Thyssen donated 650,000 Reichsmarks to right-wing parties. "Thyssen also persuaded the Association of German Industrialists to donate 3 million Reichsmarks to the Nazi Party (National Socialist German Workers' Party) for the March, 1933 Reichstag election." 
German chemicals company IG Farben, which in addition to vaccines, produced poison gases and rocket fuel for the Nazis, was the second-largest shareholder of the Rockefeller's Standard Oil. At one point, Farben was the largest company in Europe. Farben and the Rockefellers had so many joint ventures such that they both could be considered the same entity. IG Farben financed 45% of Hitler's election campaign of 1930.
The Ruhr Valley between Germany and France was the booming source of coal for both countries, providing much-needed supplies for steel and production and heating homes. The German industrialists suffered major losses with the return of Lorraine to France, and they demanded payment from Germany to compensate for the loss. They also cut down trade of coal to France, which led France and Belgium to occupy the Ruhr valley and demand the resumption of trade.
The Wall Street Crash of 1929 led American banks to call in their loans, leading to a trade crunch, such that by 1933, almost two-thirds of world trade vanished.
 Howard Zinn's A People's History of the United States
 Yuri Rubtsov
 Dawes Plan
 Young Plan
 Fritz Thyssen