Proving you have never invested in the slave trade or a gun maker would be rather simple. More difficult is to prove you sidestepped investing in factories hazardous to workers’ health. Hardest of all, though, is to prove you helped alter corporate behaviour to better the world.

That could change as more ethical fund managers make strides at influencing companies. The investment world is changing, with new rankings and corporate disclosures. Support for the United Nations-backed Principles for Responsible Investment (UN-PRI) initiative is rising, with some $30 trillion in assets committed worldwide and nearly $900 billion in Canada.

But proving who prompts change is difficult. Most executives and directors prefer to take the credit themselves, says one veteran of socially responsible investments. Sometimes, says another, the prime reason for assessing environmental risks is more to protect investors from financial losses than the world from degradation and inequity.

"It’s hard to find quantitative analysis that will give you a hard and fast answer (about investors prompting change)," says Tessa Hebb, a Carleton University professor who has already helped document the corporate intervention efforts of three fund managers and hopes to document more. "There are so many forces operating in the economy and with companies generally that it is extremely difficult to isolate the environmental, social and governance factors and the pressure of investors on those changes at the companies."

Jane Ambachtsheer of the consulting firm Mercer has been awarded a lifetime achievement award by the Social Investment Organization, which promotes socially responsible investing in Canada. Yet, when asked about the extent that such principles have changed corporate behaviour, she said: “I don’t think there is any evidence or research to show that…particularly if you narrow it to the mutual fund field.”

A pioneering manager of ethical and responsible mutual funds, the Ethical Funds arm of NEI Investments has had a few victories sponsoring shareholder resolutions – four from 11 attempts in 2009. What it does not have is much voting power. Ethical Funds runs a Special Equity Fund with the best 10-year performance among its ethical peers. Yet it and the other funds hold only about $1.4 billion in assets. Total assets reported to Corporate Knights by the socially responsible mutual funds it tracks is about $5 billion.

“The reality is that there still are structural barriers to the flow of funds (into socially responsible mutual funds),” says Bob Mann, chief operating officer of Sustainalytics. Formerly Jantzi Research, it was chosen by Newsweek magazine to do its 2011 Green Rankings report, and was flooded with questions from 300 corporations hoping to rank highly.

Mann says there is anecdotal evidence that Canadian investors wanting to invest by their values often hit a wall. They "have been discouraged or turned away, or found their broker didn’t have the information," Mann says. By contrast, he notes, assets spiked in Australia after the country began requiring brokers and mutual fund advisers to ask new clients if they are interested in responsible funds.

Even if the ethical and responsible investment funds had more in their arsenal than the art of persuasion, Mann doubts they would get full credit for prompting change. “Engagement (with corporate executives on social and environmental issues) has rapidly increased. Investors are more willing to go out there and use their ownership stakes to actively create change,” he says. Large pension funds hire companies like Hermes Equity Ownership Services and the engagement arm of F&C Investments in the United Kingdom to press companies for change. Despite all of their efforts, says Mann, “what companies don’t like to do is to look like they are caving (under pressure). They don’t want to lose face. So companies doing the engagement agree not to go public.”