The Deep Space Network has only three 70-meter dishes, and there is a lot of competition for time on them; New Horizons is lucky to get one communications session per day. And while New Horizons is pointing its dish at Earth, it can't point at anything else, including Pluto.
Saudi Aramco is deservedly #1 on this list. This company generates over $1 billion a day in revenue, produces the most barrels per day of any company and is sitting on the largest proven reserves in the world. This company began with Standard Oil of California striking oil in Saudi Arabia in the 1930s.
The dominant company is Petroleos de Venezuela, PDVSA. Venezuela is one of the five founding OPEC countries. The very idea of OPEC itself was proposed by Venezuelan Juan Pablo Perez Alfonso, in response to low oil prices in August 1960.