Impact investment funds are growing in prominence, with GPs keen not to miss out and feel green with envy as investors seek to make financial returns while also having a positive impact on the world. Though far from a new trend, in private equity inflows are rising in to this asset class that is estimated to be worth $1.2 trillion. With TPG raising $7.3 billion for its sixth impact fund, other prominent names are stepping in to focus on green investments, including KKR who just raised $2 billion for their second such fund. As the trend develops, there are calls among regulators to tighten up how GPs quantify the ‘impact’ of these funds and avoid greenwashing. It is not inconceivable that the industry ends up with 50 shades of green, if more impact funds come to market. How GPs define their ambitions, and measure them, will be watched closely by investors and regulators alike.