The New Zealand Superannuation Fund produced a 4.29% return in March, bringing its returns for the financial year to date to 22.3%.
The fund made a net gain in investment income, after fees but before tax, in March of $679 million, lifting the fund's value to $16.6 billion.
The fund's strong performance since July 2009 is in marked contrast to a loss the previous financial year of 22.1% and a 4.9% decline in 2007-08, reflecting a recovery in international markets after the global financial crisis.
The largest proportion of total fund investment is in large cap international equities (37.3%), followed by international fixed income (15.8%) and global listed property (7.8%).
Currently, 6.9% of the fund is invested in New Zealand equities, including an ever declining investment in Telecom, which was worth $100.2 million compared with $107.7 million at the end of February.
Telecom has slipped to the fund's fourth-largest investment in local equities, behind Auckland International Airport, Fletcher Building and Contact Energy.
The fund was set up by the previous Labour-led government to help smooth out the future costs of New Zealand superannuation by investing government contributions and returns on the contributions over the long-term.
In last May's budget, the government revealed plans to suspend payments to the fund for at least a decade to help reduce Crown debt.
However, last week Finance Minister Bill English said the government could resume contributions within six years as the economy was improving faster than expected.
The fund has received a total of $14.88 billion in government contributions, and has produced annualised absolute returns of 6.6% since its inception.
The fund's long-term target was to exceed the rate of return on Treasury bills by 2.5% over rolling 20-year periods.