These Are The Ten Most Profitable Companies In Illinois Illinois is among the top five U.S. states in terms of GDP size and is one of the most diversified economies. As can be expected, the economy of Chica... Free Book Preview Money-Smart Solopreneur This book gives you the essential guide for easy-to-follow tips and strategies to create more financial success. Email This story originally appeared on ValueWalk Illinois is among the top five U.S. states in terms of GDP size and is one of the most diversified economies. As can be expected, the economy of Chicago contributes immensely to Illinois’ GDP, making the state a global financial center and headquarters of many big financial institutions. The state is also home to the largest futures exchange in the world, the Chicago Mercantile Exchange. Let’s take a look at the ten most profitable companies in Illinois.