Kohlberg Kravis Roberts, the New York City–based investment firm, has closed a $3.1 billion global fund aiming to make infrastructure investments in energy supply chain, water systems, roads, railways, airports and communications networks. The fund’s principal geographic targets will be projects in countries that are members of the OECD — an organization that represents 14 nations including Australia, Canada, Estonia, Germany, Mexico, Norway, Poland, Turkey and the United States, among others.