The New Zealand Superannuation Fund says the return on its investments edged up last month.
The fund, which was set up to help fund future retirement payments, reported a 1.4 percent return in April.
On an annual basis, returns rose 18 percent.
Since it started in September 2003, the fund's return after fees but before tax is 9.55 percent.
The fund, which has 62 percent of its assets in global equities, totals $25.5 billion.
It does not give reasons for monthly movements in its performance, saying it takes a long term view of investing.