At the beginning of the 2000s, the salary bump from getting an MBA in the U.S. was 50% greater than that from a European MBA, but over the subsequent decade the gap declined almost to zero as European companies began to view business degrees as highly desirable, say François Collet and Luis Vives of Ramon Llull University in Spain. One consequence has been a rise by non-U.S. institutions in business-school rankings, which are heavily dependent on post-MBA salaries. For example, in 1999, 9 out of the top 10 business schools in the Financial Times Global MBA Rankings were located in the U.S., but by 2010 the number had declined to 6.

Source: From Preeminence to Prominence: The Fall of U.S. Business Schools and the Rise of European and Asian Business Schools in the Financial Times Global MBA Rankings