After WWII, having learned an invaluable lesson and ready to avoid making the same mistake again, the US instated the Marshall Plan, $17 billion ($120 billion in today's money) in aid to prevent the local economies going into a free-fall, and rebuild Europe.
This is a common myth that is still present in history books today. Germany got only $1.4 billion of the Marshall plan aid which is about $15 billion today. Furthermore the allies took reparations by dismantling part of the German industry and confiscating intellectual property.
Contrary to common myth, the US did in fact take "reparations"; parts of it by John Gimbel called "plunder and exploitation", directly from Germany. The US for instance took an 8.9% share of dismantled Western German industry.
The Allies also confiscated large amounts of German intellectual property (patents and copyrights, but also trademarks). Beginning immediately after the German surrender and continuing for the next two years the US pursued a vigorous program to harvest all technological and scientific know-how as well as all patents in Germany. John Gimbel comes to the conclusion, in his book "Science Technology and Reparations: Exploitation and Plunder in Postwar Germany", that the "intellectual reparations" taken by the US (and the UK) amounted to close to $10 billion. The US competitors of German firms were encouraged by the occupation authorities to access all records and facilities. In 1947 the director of the US Commerce Department's Office of Technical Services stated before congress: "The fundamental justification of this activity is that we won the war and the Germans did not. If the Germans had won the war, they would be over here in Schenectady and Chicago and Detroit and Pittsburgh, doing the same things."A German report from May 1, 1949 stated that many entrepreneurs preferred not to do research under the current regulations (Allied Control Council Law No. 25) for fear of the research directly profiting their competitors. The law required detailed reporting to the Allies of all research results.
The patents, drawings and physical equipment taken in Germany included such items (or drawings for) as electron microscopes, cosmetics, textile machinery, tape recorders, insecticides, a unique chocolate-wrapping machine, a continuous butter-making machine, a manure spreader, ice skate grinders, paper napkin machines, "and other technologies - almost all of which were either new to American industry or 'far superior' to anything in use in the United States."
The impact of the Marshall plan becomes even more insignificant if you consider that the allies charged Germany $2.4 billion per year for the occupation. The Wirtschaftswunder can largely be attributed to the economic reforms under Ludwig Erhard.