Nomura's Rick Sherlund called Mulally's withdrawal "disappointing" in a research note, echoing the sentiment of some other investors and analysts. Sherlund said it was unclear who the board would turn to, saying he viewed Bates and Nadella as capable, but "more likely to take direction from Microsoft's board rather than redirect the board and take the company in a different direction as we prefer." If the company does opt to go with an outsider, candidates could include Facebook Inc Chief Operator Officer Sheryl Sandberg, VMware Inc CEO Pat Gelsinger and Pivotal CEO Paul Maritz, Ives said. Whoever takes over the tech behemoth is expected to transition it to mobile phone and tablet markets, where it has been a latecomer.