The organisation said its tenets of what impact investing should be are needed at a time when the overall sector is rising fast, even if it is dwarfed by the overall financial market.

A global network advocating and monitoring best practice around impact investing has launched tests to ensure that financial players get a clearer view of this market and that practitioners adhere to high standards.

The Core Characteristics of Impact Investing are four tenets that are being laid down by the Global Impact Investing Network, aka GIIN.

The tenets seek to promote understanding of the essential elements of impact investing, define if their practices are credible, and test the rigour of investment partners.

Impact investing involves using money to generate non-financial as well as monetary returns, such as cutting criminal re-offending, reducing illiteracy, cleaning up the environment and helping women in the workplace. The term has gained currency in recent years and in some ways straddles philanthropy and investing. As the sector has grown, it has caused concerns that inflows of money might erode the quality of investment projects, a situation sometimes dubbed "mission drift". GIIN's initiative is designed to keep impact investing standards high.

"We are launching these Core Characteristics at a critical time in impact investing; the next couple of years will either see it remain on the fringe of the financial markets or press forward into the mainstream,” Amit Bouri, GIIN chief executive and co-founder, said.

“To tackle issues on the scale of the Sustainable Development Goals and global climate targets, we must think much bigger and engage a much broader set of investors. Scale is essential. But it must be scale with integrity, to ensure we are achieving impact at scale, not just capital at scale," Bouri said.

GIIN recently reported that the impact investing market size sits at an estimated $502 billion. Impact investing is still small compared with the overall investment universe. The market capitalisation of the world's 10 largest markets was a combined $89.85 trillion in April last year (source: Statista) - that figure is likely to have eroded slightly after equities declined in 2018.

The Core Characteristics of Impact Investing include:

-- Intentionality: Impact investing actively sets out to positively contribute to social or environmental solutions by establishing clear impact objectives and thorough strategies to achieve these goals ahead of execution;

-- Evidence-Based Investment Design: Impact investing utilises evidence and impact data in the design of the impact strategies;

-- Impact Management: Impact investing requires commitment to impact measurement and management of an investment towards meeting intended objectives and delivering impact; and

-- Contribution to Industry Growth: Impact investing necessitates a practice that is grounded in shared conventions and standards for describing impact goals, strategies, and performance.