The managing director of State Street Australia, the Boston bank’s local investor services/custody operation, has unexpectedly resigned less than four months after returning to the country.

New Zealand-born Peter Baker relocated to Sydney in January from Singapore, where he had run investor services for Asia ex-Japan since October 2006, following a stint running the UK unit. Prior to that, he had headed the custody-based business in Australia from 1997 until 2004.

It had been intended that Baker would replace David Travers, who was retrenched from his role running State Street Australia in December. Wider responsibilities had also been envisioned for Baker, according to Peter O’Neill, who now oversees State Street’s investor services and trading businesses in the Asia-Pacific from Hong Kong.

“I’m saddened by the decision of Peter Baker to move on, I have the highest professional respect for him…our job now is to find a way to replace him,” O’Neill said.

Baker said he had personal reasons to be spending more time with his family in New Zealand. He will continue as head of the Australasian investor services business for another two months, and then spend six months helping to shape State Street Australia’s strategy for the next three years, before departing in December.

The head of operations for the regional asset servicing business, Michael Brager, has temporarily relocated from Hong Kong to Sydney to assist the transition.