The $18 billion Sunsuper will choose State Street Corp. or National Australia Bank Ltd. (NAB) as its custodian as the fund enters the final stages of a long tender, people familiar with the matter say.

The decision to appoint either State Street or NAB, which has provided custodial services to Sunsuper for 13 years, hinges on the front- and back-office capabilities of each custodian.

Sunsuper’s Sydney-based investment team is impressed by the market analytics provided by State Street, the people say. The fund’s investment operations team in Brisbane is satisfied with NAB’s services.

Bruce Wilson, chief financial officer at Sunsuper, says the fund tendered its custody contract after observing improvements in the services offered by custodians in recent years.

“We’ve had many years of good service from NAB,” Wilson says. “We are going to market for governance reasons.”

Sunsuper appointed Mercer Sentinel in March to assess offerings from selected custodians.

Lounarda David, Asia-Pacific director at the investment operations consultant, and Jamil Barmania, senior associate, conducted the search.