Taxes on income and capital defined to include gains and payroll taxes and to cover substantially similar future taxes. Taxes on income and on capital under the Agreement include all taxes imposed on behalf of a Contracting State or its subdivisions regardless of how levied, covering taxes on total income, total capital, elements of income or capital, gains from alienation, and the payroll tax; the treaty lists principal existing taxes as examples and extends to identical or substantially similar taxes enacted after signature, with competent authorities required to notify each other of significant changes in taxation laws.