RIM (Blackberry) was kind of infamous for it.
...the co-CEO structure is very unusual, although some high-profile technology companies, including Motorola and Wipro, in addition to RIM, have adopted it.
“Two CEOs with complementary skills and knowledge could presumably lead a firm better (compared with single CEO) and deliver better performance,” she added. “In addition, it might be helpful in retaining good CEO-material employees and avoid having them leave the firm and take their valuable knowledge with them elsewhere, especially if there was an exodus.”
However, Danielova adds, there are probably many more drawbacks to such a structure.
https://www.ibtimes.com/why-does-rim-have-two-ceos-299195