Impact Investing and Measuring Impact: Additionality, Theory of Change and the Listed-Equity Debate

What you will learn

• The three features of impact investing in the usual definition: intention, measurability and a financial return.
• What additionality means and how to test whether your money changed anything.
• How a theory of change links inputs, activities, outputs, outcomes and impact, and how the five IMP dimensions organise measurement.
• Why "impact" claims by funds that buy listed shares on the secondary market are contested.

Explanation

Impact investing is usually defined, following the Global Impact Investing Network (GIIN), as investing with the intention to generate positive, measurable social or environmental outcomes alongside a financial return. Lesson 1 placed it on the spectrum; here we look at how impact is claimed and measured.

Additionality is the central test. An investment is additional if the positive outcome would not have happened without it. Three channels can create additionality:

• Capital additionality: the project could not have been financed otherwise, or only at much higher cost. Realistic in primary markets (new shares, new loans, project finance) and under-served areas such as microfinance.
• Non-financial additionality: the investor brings expertise, networks or governance.
• Signalling and engagement: the investor's presence changes the behaviour of the company or other investors (lesson 10).

When you buy a share on an exchange, the money goes to the previous owner, not to the company. This is why the impact of secondary-market equity funds is contested: the fund owns a slice of a company that may do good things, but buying the slice did not make them happen. Berk and van Binsbergen ("The Impact of Impact Investing", Journal of Financial Economics) estimate that today's sustainable-investor demand changes targeted firms' cost of capital by well under one basis point, far too little to alter investment decisions. A listed-equity fund can honestly claim alignment and perhaps influence through voting and engagement; it should not claim that your purchase funded the solution.

A theory of change is the written chain of logic from money to outcome:

1. Inputs: the capital and the support provided.
2. Activities: what the investee does with it (builds mini-grids, lends to small firms).
3. Outputs: countable results (households connected, loans made).
4. Outcomes: changes in people's lives or the environment (hours of light, income growth, tonnes of CO2 avoided).
5. Impact: the outcome minus what would have happened anyway, adjusted for the investor's contribution.

The Impact Management Project (IMP) convention describes each investment along five dimensions: What outcome, Who experiences it, How much (scale, depth, duration), Contribution (the investor's additionality) and Risk that the impact fails. The GIIN's IRIS+ catalogue standardises metric definitions. A fund that reports outputs with no counterfactual is reporting activity, not impact.

For a private investor in Germany, genuine impact products are mostly closed-end funds, direct lending platforms, microfinance funds or development-bank bonds. They are often illiquid, carry higher fees, and in some structures you can lose everything. Impact is not a safety feature.

Worked example

Hypothetical example: an impact fund invests EUR 5 million in a company that builds solar mini-grids in rural areas with no grid connection. The fund's report says: "Our investment connected 20,000 households."

Step 1 – cost per output. EUR 5,000,000 / 20,000 households = EUR 250 per household connected. This is an output figure.

Step 2 – counterfactual. A baseline study (assumed) finds that about 30 % of these households would have obtained a connection within the same period anyway, through a government programme. Additional connections = 20,000 × (1 − 0.30) = 14,000.

Step 3 – cost per additional output. EUR 5,000,000 / 14,000 = EUR 357.14 per additional household. This is 42.9 % higher than the headline figure, because 357.14 / 250 = 1.4286.

Step 4 – contribution. If the fund provided 50 % of the project's capital and a development bank joined only because a private co-investor did, the fund can claim a large share of the impact. If it bought a 5 % stake from an exiting founder, its contribution is near zero even though it "owns" a share of 14,000 connections.

Step 5 – outcome. Outputs become outcomes only with further data: for example, household kerosene spending falling from EUR 6 to EUR 2 per month saves EUR 48 per year; 14,000 × EUR 48 = EUR 672,000 of yearly household savings (assumed numbers).

Assumptions: all figures invented; fund fees, currency risk and default risk of the company are excluded.

Common mistake

Practice activity

On paper: a microfinance fund lends EUR 2 million through a local institution, enabling 8,000 small loans with an average size of EUR 250. A study estimates that 25 % of the borrowers could have obtained a similar loan from another lender at a comparable cost. Calculate (a) the cost per loan enabled, (b) the number of additional loans, (c) the cost per additional loan. Then name one output metric and one outcome metric the fund should report.

Key takeaways

• Impact = intention + measurement + financial return; without a counterfactual, "impact" is just activity reporting.
• Additionality is strongest in primary markets and weakest when buying listed shares from another investor.
• Use the theory-of-change chain and the five IMP dimensions to judge a fund's impact report.
• Genuine impact products are often illiquid and can lose all your capital; impact does not reduce financial risk.

Next step

Lesson 9 moves to the bond market, where "use of proceeds" gives a much clearer link between your money and a project: green, social and sustainability-linked bonds.