The growing asset portfolio of the Canada Pension Plan could prove to be an irresistible source of funds for future cash-strapped governments, the C.D. Howe Institute warned in a report published yesterday.

It called on all stakeholders to reaffirm that the money in the CPP should be used for only one thing: to pay benefits.

Report author William Robson said the record of many public pension plans around the world in serving the interests of their citizens has been “appalling,” noting that a World Bank survey found that half of them lost money over an eight-year period.

Robson is the director of research at the C.D. Howe Institute and is the president of Northern Analytics Inc.

So far, Robson says Canada hasn’t embarked on “the slippery slope of politicized investment.” But he warns that subtle pressures are already building to have the CPP act in ways that would take it away from its current mandate of maximizing returns without undue risk of loss.

Already, he sees cracks. The 2006 federal budget, for instance, proposed to put extra surpluses into the CPP’s fund.

“Create a hole through which money repeatedly flows between the two, and the odds are high that one day the flow will go the other way,” he said.

Robson cites data that suggest the CPP’s reserve fund is growing much faster that other sources of government funds. The current $98 billion CPP asset base is now equal to almost half of the federal government’s annual revenue. By 2028 or so, he notes, the CPP’s reserve fund will be bigger than government revenue.

“As the CPP’s provident fund grows, governments under pressure to deliver on their promises to provide health care, education and infrastructure to a tax-weary population will inevitably look covetously at the fund,” Robson writes.

He said it’s not too early to have the CPP Investment Board and governments reassert that CPP funds have only one purpose — to pay benefits to plan members.