More generally: From my (limited) experience 90% of the executives studied law or economics and simply worked for the company long enough to out live all competitors. At one the "Big four" companies I worked for the managing director had a degree in strict sciences, and worked his/her way up by specialising in security in the financial sector.

Three psychological factors before they got to the highest echelons: they were efficient, they knew the business VERY well, and they liked taking risk (many did extreme sport like freediving etc.).