If Jack Dorsey becomes permanent CEO of both Twitter Inc (TWTR.N) and mobile payments company Square, he could struggle with conflicts of interest in the business that is key to both companies’ futures: e-commerce. Corporate governance experts and some investors have already expressed concern that Dorsey faced tough choices in his role as interim Twitter chief and head of Square. Dorsey has acknowledged the risk of a conflict of interest, publicly saying he recuses himself from decisions involving both companies.