GNP: total value of all materials, foodstuffs, goods, and services produced by the companies of a country in a particular year. GNP measures the nationality of production so an American Ford Motor Company auto-assembly plant in Mexico contributes to the American GNP. Currently, 80% of Ford's employees are employed overseas.

GDP: Gross Domestic Productan estimate of the total value of all materials, foodstuffs, goods, and services produced within the borders of a country in a particular year. GDP measures what is produced within the borders of a country regardless of ownership. In this case, the American Ford Motor Company auto-assembly plant in Mexico contributes to the Mexican GDP.

Transnational corporations:
companies that participate not only in international trade but also in production, manufacturing, and/or sales operations in several countries.

That individual corporations dwarf the national economies in which they operate made GNP problematic. That's why they changed their measure to GDP.

Redefining Progress: Projects: Genuine Progress Indicator
GENUINE PROGRESS INDICATOR. ... In 1995, Redefining Progress created a more accurate measure of progress, called the Genuine Progress Indicator (GPI).
www.rprogress.org/projects/gpi/