AustralianSuper expects to grow to over two million members and $50 billion worth of member assets, after IBM selected it as its default superannuation fund.
The transfer of IBM Super members to AustralianSuper, subject to due diligence, will add 15,000 members and increase funds under management (FUM) by $1.7 billion.
An AustralianSuper spokesperson said the deal was the "largest ever corporate outsourcing in history".
AustralianSuper chief executive Ian Silk said the fund's increasing scale allowed it to provide sustainable results for members.
"IBM's decision is an endorsement of our members-first strategy," he said.
AustralianSuper merged with Westscheme in July 2011, adding $3.4 billion to AustralianSuper's FUM, and is also set to join up with AGEST Super.
If all goes according to plan, IBM Super members and employees will transfer to AustralianSuper on 1 November this year.
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