The theme running through all infrastructure investment is the tremendous need. In 2013, the McKinsey Global Institute estimated $57 trillion in infrastructure investment would be required between 2013 and 2030 just to keep up with global GDP growth. That $57 trillion projection was more than the estimated value of the entire worldwide infrastructure stock at the time. As large as it is, even this estimated amount will not be sufficient to address major backlogs and deficiencies in infrastructure maintenance and renewal or meet the broader development goals of emerging economies.

Accessing infrastructure assets by providing financing at various points in the debt stack is often the most attractive play for investors. Rather than risking equity for what are often fixed-income-like returns, investors look to just treat the assets as fixed-income and provide debt.

Debt funds, however, are not growing the way you might assume they would given the attractiveness of infrastr