Social infrastructure today is probably the smallest infrastructure sector as measured by the value of private financing. Investments in everything from hospitals and schools to courts and municipal buildings — social infrastructure — are typically structured as public-private partnerships in which an investor, over a long term, can enjoy a stable revenue stream defined upfront.

Stocks or equities, fixed income or bonds, and real estate or other tangible assets — these are the big contenders; the kinds of assets your mind will most likely land on when considering what kind of investments a portfolio should contain in the current investing environment.

As the editor of a U.S.-based publication focused on private investment in infrastructure, I often get asked, in one form or another, “Why can’t the United States get its act together and fix its infrastructure?” That is more than a fair question, the premise of which is usually centered on the United States’ reputation as the world’s leading capitalist economy. “If private investment in infrastructure is going to work anywhere, it should work in the United States,” the thinking goes.