FT reporter Owen Walker reports that the Global Impact Investing Network an industry body of more than 1,300 impact investors worldwide, now puts the size of the impact investing market at $502 billion. This is double the sum of previous attempts to quantify the value of assets dedicated to impact investing, which treats societal and environmental outcomes as equal to financial returns.  

But with that rapid growth come concerns that some fund managers are marketing themselves as impact investors but doing little to produce the non-financial outcome clients expect.