The USA was a creditor country. Since WW2 the most important factor determining the economic development has been the scientific and technological revolution. Automation has completely changed conventional production methods. It eliminated smaller and financially weaker competitors. Every big firm has its own research centre.

INDUSTRY
Industry plays the leading role in the national economy. The most important industrial groups are: transportation equipment, food products, chemicals, mechanical engineering, electrical and electronic engineering, textile and leather, metal manufacturing, iron and steel, construction materials.

ENERGY
The primary sources of energy are petroleum (oil), natural gas and coal. Although industrial production is now widely dispersed all over the U.S. and since WW2 many industries have moved south, the greatest concentration of industries is still to be found in 3 main areas: the North-east, the Lower Lakes Region in the Middle West, and the Pacific states in the West. The main industrial area in the South is Texas. The mountain Region of Colorado, New Mexico and Arizona is known for the mining industry. In each branch of industry there is a number of big corporations concentrating most of the production, e.g.:
 in the automobile industry - General Motors, Ford, Chrysler
 in petroleum industry - Exxon, Texaco, Mobil Oil, Gulf Oil, Standard Oil of California
 in electrical and electronic engineering industry: General Electric, International Business Machines (IBM), ITT/-Bell
 in chemicals - Du Pont de Nemours, Union Carbide, Kodak, Polaroid
 some other well known corporations - U.S. Steel, Coca Cola, Burlington Industries (textiles), Avon Products (cosmetics), Xerox, Gillette, J.C. Penny, etc.

All these are controlled by one of the monopoly groups, of which there are about 20. The biggest of are the Morgans, the Rockefellers and the du Pont Group.

THE MORGANS control through their banks about a quarter of the biggest corporations, including U.S. Steel, General Electric, IBM, Kodak, ITT and others.
THE ROCKEFELLERS control the oil corporations.
Another family group is THE MELLON family.