Canadians who want to steer clear of investing in gun companies are out of luck if they pay into the Canada Pension Plan.

CPP owns shares in American firearm manufacturers, including the parent company of handgun manufacturer Smith & Wesson, assault rifle maker Ruger and Olin Corp., which produces ammunition for the AR-15, the weapon of choice for many perpetrators of mass shootings.

The holdings are highlighted in a new report coming from Corporate Knights, a Canadian magazine focused on ethical investing, and come after another bloody weekend in the U.S., where seven people were killed and 25 injured in a mass shooting in west Texas.

"CPP does have systems in place to weed out some ethically egregious stocks," said Toby Heaps, who publishes Corporate Knights. "But I think they've made a call that there's not necessarily a consensus on gun stocks."

Heaps pointed out that CPP's holdings in firearms firms are small relative to the overall size of the plan — about $37 million Cdn worth of stock out of the $400 billion it manages. But he said many other public pension funds have opted to bail out of the category entirely.

Toby Heaps, publisher of Corporate Knights, said many public pension funds have stopped investing ion the gun industry altogether.

"The Alberta pension fund doesn't own it anymore, the B.C. pension fund and the Caisse in Quebec don't own it," Heaps said. "It appears there is a bit of a pan-Canadian consensus, at least among their peers in pension funds, that these stocks are too hot to touch."

'Weapons definitely out'

Toronto-based independent contractor Tina Lopes is "upset" that a portion of her monthly contributions to the Canada Pension Plan is used to invest in gun companies.

"I want to make sure that my money isn't doing harm," said the mother of three. "I don't want to profit from companies, manufacturers or industries that could potentially harm people."

Lopes has spent most of her career focused on social justice issues, working with child welfare agencies and school boards. Ethics are a prime concern for her, so she hired an ethical investment planner earlier this year to help her design a suitable portfolio.

"I told him weapons are definitely out, oil was out, and tobacco. And I also have a commitment to climate change," Lopes explained.

The planner she hired is Tim Nash, who runs a consultancy called Good Investing. Nash said a growing number of his clients are concerned about weapons. "Guns and also broader military companies are probably at the top of the list when it comes to exclusions," he said.

Gun stocks 'underperform'

For many Canadians, however, the number one consideration when it comes to investment is profitability. CPP has the same priority.

"Our critical purpose is to help provide a foundation upon which 20 million Canadians build their financial security in retirement," reads a statement on its website.

But weapons aren't even a great moneymaker these days, said Heaps.

"Some people think, oh, if CPP has gun stocks, they must be making some good profit. But what we've noticed with gun stocks is that they tend to underperform," said Heaps. "All these stocks have underperformed the market over the past five years."

So why hold them at all?

CBC News contacted the Canada Pension Plan Investment Board in the hope of learning more about its rationale, but received only a four-word email in response: "We decline to comment."

Heaps believes CPPIB "wants to do the right thing," but that it simply hasn't received much feedback so far on the subject of investment in firearms.

"I think if enough people express their disdain and write or phone the Canada Pension Plan, this is something that will rise to the top and they will say this is clearly offside [for] Canadian values."

Not just CPP

Earlier this year, NDP member of Parliament Charlie Angus tabled a bill in the House of Commons related to CPP, specifying that "no investment may be made or held in any entity that has performed acts or carried out work contrary to ethical business practices or has committed human, labour or environmental rights violations."

Investment planner Nash would also like to see change. "What we need to do is to continue to push CPP towards adopting more stringent socially responsible investment policies."

He cautions, however, that it's not just CPP that invests in guns. Many mutual funds do, too.

"Unfortunately, it's quite common that guns are inside of mutual funds and ETFs [exchange-traded funds], unless you have a mutual fund that is explicitly socially responsible," Nash said.

Heaps said Corporate Knights's report on controversial stock holdings will detail the Canadian mutual funds and pension plans that own them, and will appear in the November issue of the magazine.

"Doctors investing in tobacco, dentists investing in Coca-Cola, teachers investing in guns, investment in the climate crisis," Heaps said, rhyming off some of the findings. "I think many people will be surprised at what they're into."