New Zealand Post is sell its stake in Datacom Group, an information and technology company, for $142 million.
The State postal operator said the New Zealand Superannuation Fund bought its 35% holding.
The deal will result in a gain of $76.4 million, which chief executive Brian Roche said will be used to repay debt and invest in other parts of its business.
"It would have been nice to have kept it but given the other capital priorities we have in the group we thought it was better to liquidate it now, get the $142 million and deploy it to other capital needs and to retire some of our debt."
Mr Roche said New Zealand Post will remain a significant customer of Datacom.