This fund outperformed the markets in 2015, but you're probably not allowed in. Unless you're Singaporean or near enough.
Singapore's Central Provident Fund (CPF), a mandatory retirement savings plan open only to the country's citizens and permanent residents, offered its usual, steady 2.5 percent-to-5 percent payouts, depending on the nature of members' balances.
But that compares with an essentially flat S&P 500 year-to-date and a near-15 percent drop in the Singapore Straits Times Index over the same period. Other assets haven't done well either: The SPDR Barclays High Yield Bond Exchange Traded Fund (ETF) has mirrored a tough year for junk bonds, dropping more than 12 percent year-to-date.
Singapore's private residential property prices have ticked lower as well, falling 1.3 percent on-quarter in the third quarter after slipping 0.9 percent in the previous quarter.
All of these factors made the CPF a much more attractive prospect that one might have imagined, for those eligible to save with it.
The last time CPF returns outperformed the S&P 500 was 2011, during the European debt crisis, when the index fell 0.9 percent. In 2011, the CPF pegged the payout to 1 percentage point above Singapore government securities. At the beginning of 2011, the 10-year Singapore government bond was yielding around 2.7 percent, but by the end of the year, that had fallen to around 1.6 percent.
Tony Nash, chief economist at Complete Intelligence, blamed the "cat-and-mouse game that the Fed has played with market investors this year" for the paltry returns available in financial markets, adding that market expectations for a Federal Reserve interest rate hike had been building since June.
In early December, the Fed finally raised interest rates by 25 basis points to an 0.25 percent to 0.5 percent range, its first hike in nearly a decade.
"Expectations around higher interest rates (created) muted expectations for equity returns," said Nash, who noted that he, too, is a CPF account holder. Expectations that the Federal Reserve would increase rates led to fund outflows from riskier assets, such as equities. After a rate increase, higher returns from lower-risk securities, such as U.S. Treasurys, make riskier assets less attractive to investors. Additionally, higher rates can also impact corporate earnings as interest costs rise.
The CPF payout rate is set at the higher of the 2.5 percent minimum or a computed rate based on the 12-month savings deposit rate at local banks. After years of low yields globally, that rate would likely be around 0.2 percent, making the 2.5 percent minimum look generous.
But CPF returns can be politically contentious in Singapore - which isn't surprising when most workers aged 50 and below are required to pay in around 20 percent of their wages; that cohort's employers also pay in about 17 percent of workers' wages.
Money paid into the CPF is invested into Special Singapore Government Securities, or bonds guaranteed by the government, which are considered risk-free assets. The government then passes the funds to one of its sovereign wealth funds, GIC, to manage the proceeds. For the year ended March 31, GIC reported a 20-year annualized return of 4.9 percent.
And it's not all roses for CPF members, even in tricky times for financial markets.
The government's moves in recent years to increase the minimum age for collecting some of the funds, in line with life expectancy increases, and to increase the "minimum sum" which must be set aside as an annuity, in line with inflation, have proved unpopular. Starting in 2016, the program will allow more flexibility in withdrawing funds from age 55, but that can result in lower payouts in retirees' golden years.
The interest rate paid on CPF balances is also a point of contention. During a national election in September, opposition candidates pushed to increase the payout, with one even reportedly calling for a 15 percent return. (He didn't win a seat in parliament.)
By comparison, Singapore's 10-year government bond currently yields about 2.5 percent.
The return on the U.S. Social Security program - which unlike the CPF's defined-contribution model is a defined-benefit plan -- was estimated at about 6.5 percent at its best at the end of 2014, but can vary per person.
CPF contributors may grumble about the returns, but they aren't always doing terribly well on their own in the broader markets. One quirk of the program is allowing some members to invest some of their funds in approved securities.
For the financial year ended September 30, 2014, the most recent data available, only about 15 percent of the participants who sold investments posted a net realized profit in excess of 2.5 percent and 45 percent posted profits equal to or less than 2.5 percent, while around 40 percent posted losses.
—By CNBC.Com's Leslie Shaffer; Follow her on Twitter @LeslieShaffer1