The company's assets grew 25% to 2.22 billion kina in 2010 on the back of work starting on the PNG LNG project and the aftermath of the global financial crisis having a bearish effect on markets.
Meanwhile, the fund attracted 11% more members, 9% more employers and 27% more contributions year-on-year.
The 15% return is the envy of most funds in Australia, and even taking in a PNG inflation rate of 7-8%, Nasfund has managed to outshine Aussie funds.
However, the company warned that as 2011 rolled on, it would become clear that the engines driving capital appreciation in PNG would peak.
In addition, a stronger kina would negatively affect overseas equities, such as Oil Search, New Britain Palm Oil and Steamships Trading.
Seeing stormy weather ahead both domestically and internationally, the fund has taken some of the return from 2010 and parked it in reserves.
Nasfund maintained a management expense ratio of 1.12%, unchanged from 2009, which is a rate that compares favourably with industry funds in Australia.