The study assessed 60 funds and nine government pension funds.
Sovereign wealth funds (SWFs) have made progress in transparency and accountability since 2007, but many still fall short of what the citizens of their country or the international community should expect, according to a think-tank study.
The paper, authored by Sarah Stone and Edwin Truman under the auspices of the Washington-based Peterson Institute for International Economics, assessed 60 funds and nine government pension funds, then scored them on elements such as governance, structure, transparency, accountability and behaviour.
The average score for the 60 SWFs was 62 percent while the government pension fund average score was 87 percent, according to the study, whose results were released on Friday.
Perhaps not surprisingly, Norway's $888 billion SWF topped the scoreboard, followed by New Zealand's Super Fund, with scores of 98 percent and 94 percent respectively. But Azerbaijan's state oil fund SOFAZ came fourth with a score of 92 percent, and two Chilean funds also made the top 10.
"One often hears that SWFs from emerging market and developing countries are non-transparent and consequently not as accountable ... The scoreboard results refute this generalisation," the authors wrote.
Many funds have substantially improved their scores over the decade since the first scoreboard, with the 33 funds assessed in in 2007 raising their average score from 51 to 67 percent.
The authors suggested the growing influence of the International Forum of Sovereign Wealth Funds (IFSWF) may have played a part in this, through the development of the Santiago Principles, which were designed to promote good governance, accountability, transparency and prudent investment practices.
They highlighted Nigeria's Sovereign Investment Authority, which as a new IFSWF member increased its score by 58 percentage points to 76 percent between the third scoreboard, published in 2013, and the latest.
They also noted that members of IFSWF in general ranked more highly on the SWF scoreboard.
However, they added that one might have expected more improvement from the funds that scored below 80 percent in 2007.
Nine of these 21 funds recorded less than double-digit improvements by 2015, including the UAE's Istithmar World and Russia's National Welfare and Reserve Fund.
Equatorial Guinea's Fund for Future Generations was at the bottom of the table, scoring 11 percent, while Istithmar World scored 23 percent, alongside the Libyan Investment Authority.
"A large number of funds fall short of what the citizens of their countries or the international community should expect from these funds, in particular the large funds, with regard to their transparency and accountability," the authors wrote.