Canada's national pension plan had $161 billion in assets at the end of its recently-completed fiscal year, up from $148 billion the previous year.

The Canada Pension Plan Investment Board said the fund gained $13.4 billion during the year — $9.9 in new investment income and $3.9 billion from new CPP contributions from plan members.

The CPPIB invests the funds not needed to pay current benefits for 18 million plan contributors or beneficiaries. The Chief Actuary of Canada recently reaffirmed that the CPP remains sustainable at its current contribution rate of 9.9 per cent for the next 75 years.That's based on the assumption that the fund can maintain an annual four per cent return.

The 6.6 per cent return compares with a 12 per cent increase the previous year.

"Overall, our investment programs delivered a strong performance in fiscal 2012 despite the challenging global equity markets over the past year," the fund's CEO David Denison said.

Canadian stocks lost ground

Gains in the fund's investments in real estate, infrastructure, private markets, fixed income, foreign securities and U.S. equities were more than enough to offset a decline in the value of Canadian equities.

Shares in publicly traded Canadian companies were the major drag on the fund's performance, losing 10.7 per cent of their value in fiscal 2012. That compares to a 20.3 per cent gain in 2011.

Indeed, the fund reduced its exposure to Canadian equity markets during the year. Some 8.8 per cent or $14.2 billion of the CPP's assets are now in Canadian equities. That's down from $21 billion last year. And the figure is dwarfed by the 41.6 of the fund's assets that are invested in equities abroad.