National Infrastructure Development Bank Act of 2015

Establishes the National Infrastructure Development Bank as a wholly owned government corporation.

Makes the Bank's Board of Directors responsible for monitoring and overseeing energy, environmental, telecommunications, and transportation infrastructure projects. Authorizes the Board to: (1) make senior and subordinated direct loans and loan guarantees to assist in the financing or refinancing of an infrastructure project, (2) issue public benefit bonds and provide financing to infrastructure projects, and (3) pay an interest subsidy to the issuer of American Infrastructure Bonds.

Requires the Board to establish an Executive Committee to establish requirements and make recommendations for project proposals to be considered for financial assistance.

Requires the Bank to establish a Risk Management Committee, which shall: (1) create financial, credit, and operational risk management guidelines for the Bank; (2) set guidelines to ensure diversification of lending activities by geographic region and infrastructure project type; (3) create conforming standards for all financial assistance provided by the Bank; (4) monitor financial, credit, and operational exposure of the Bank; (5) provide financial recommendations to the Board; and (6) ensure that the aggregate amount of interest subsidies provided for American Infrastructure Bonds in a given calendar year does not exceed 28% of interest payable under all such Bonds.

Requires the Bank to establish an audit committee.

Requires the Board to approve criteria established by the Executive Committee for determining project eligibility for financial assistance. Sets forth criteria to be considered by the Board for each type of infrastructure project. Requires the Executive Committee to conduct an analysis that considers the economic, environmental, and social benefits and costs of each project under consideration, prioritizing projects that contribute to economic growth, lead to job creation, and are of regional or national significance.

Requires any financial assistance for an infrastructure project to be repayable from dedicated revenue sources that also secure the infrastructure project obligations. Limits the amount of assistance under this Act to 50% of reasonably anticipated project costs.

Exempts all bonds issued by the Bank from state or local government taxation.

Sets forth requirements regarding compliance of assisted projects with wage rate, domestic content, and buy American statutes.

Requires the Board to establish an American Infrastructure Bond program. Establishes in the Treasury the National Infrastructure Development Bank Trust Fund into which an amount estimated to equal the tax receipts attributable to interest payable under such Bonds is to be appropriated.