No insider knowledge, but I've seen co-leads when someone departs for three reasons:
1) Make it clear to employees, shareholders, and the public that there will be another change coming. Everyone should know that a company run by co-CEOs is unlikely to be permanent. This also helps with recruiting since outside candidates know they have a legitimate shot.
2) Set up explicit competition between the two biggest contenders to win the slot. I personally believe this is dirty and guarantees the loser to leave (which I think is net bad -- the loser was a contender for CEO for a reason).
3) Reduce the need to fill someone's shoes. By giving what was one person's job to two people, those two people can focus on their areas and excel individually without unfair comparisons to their predecessor. This is especially important when the predecessor was a public figure. Think Tim Cook comparisons to Jobs. Microsoft did this with the E&D division when Robbie Bach left (Phones and Xbox went to different people).
1) Make it clear to employees, shareholders, and the public that there will be another change coming. Everyone should know that a company run by co-CEOs is unlikely to be permanent. This also helps with recruiting since outside candidates know they have a legitimate shot.
2) Set up explicit competition between the two biggest contenders to win the slot. I personally believe this is dirty and guarantees the loser to leave (which I think is net bad -- the loser was a contender for CEO for a reason).
3) Reduce the need to fill someone's shoes. By giving what was one person's job to two people, those two people can focus on their areas and excel individually without unfair comparisons to their predecessor. This is especially important when the predecessor was a public figure. Think Tim Cook comparisons to Jobs. Microsoft did this with the E&D division when Robbie Bach left (Phones and Xbox went to different people).