According to an article in Bloomberg by columnist Nir Kaissar, Yale University recently announced that its $29.4 billion endowment could exit private investments it “deems unethical, extending a policy it has long applied to investments in public markets.”

But the article argues that the attention garnered by sustainable investing “hasn’t yet translated into investment,” at least as measure by the flow of funds into ETFs:

The industry, writes Kaissar, has a basic problem: “Investors are lost among the various styles in the sustainable investing zoo. If the industry wants to attract investors, it must first explain what it has to offer.” He cites a couple of the industry’s well-known acronyms: SRI and ESG, and how they represent “distinctly different approaches.”

SRI, it says, “attempts to align investors’ portfolios with their values, mostly by excluding companies and sectors that don’t conform with those values,” citing businesses such as alcohol, tobacco and gambling as those commonly frowned-upon. ESG, Kaissar explains, “is a completely different animal. It attempts to identify environmental, social and governance policies that, in back tests, have translated into less volatility and higher risk-adjusted returns for stocks of companies that adopted those policies.” Kaissar says, “There isn’t perfect agreement around those definitions of SRI and ESG, which is a further source of confusion. It also doesn’t help that sustainable investing has a short track record, and that early results don’t jibe with the industry’s claims.” ESG, for example, has not offered lower volatility nor has it delivered higher returns.

“Interest in sustainable investing will most likely continue to grow,” Kaissar concludes, adding, “It would help if investors understood what they were buying.”