Boreham, the managing director of IBM's Telstra relationship, also serves on the board of IBM Australia. Bullock will relocate to Shanghai for the position of vice president, IBM Systems and Technology Group.
Bullock, who has served in the Australian CEO role since April 2001, guided a number of key acquisitions for the Australian subsidiary. His career at Big Blue spans 27 years.
Boreham has been with IBM since he joined the Sydney office in 1996. He later worked in Tokyo and London. In July 2004, he helmed the Telstra account as part of the company's global strategy to appoint managing directors to top client accounts.
In 2003, the company acquired Telstra and Lend Lease's shares in IBM Global Services Australia for AU$313.5 million. Major contract wins during Bullock's time included a 10-year outsourcing deal with Qantas for AU$650 million, and a AU$500 million 10-year application management services contract with Optus.
IBM Australia reported a $117 million profit last financial year.
No external candidates were evaluated prior to Boreham's selection for the Australia and New Zealand CEO position, an IBM spokesperson said.
Bullock will commute between Sydney and Shanghai over the next few weeks as he and Boreham settle into their new roles. The appointments are effective immediately, the spokesperson said.