Examining the benefits achieved by deferring income or accelerating deductions, this text refers to the income tax systems of the United States and Japan. The United States has been at the forefront of recognizing the time value of money benefit of tax deferral and of devising methods to prevent tax deferral. Japan, on the other hand, is only gradually placing greater emphasis on tax deferral issues, in light of the activities of foreign companies, and the constant introduction of new financial products which take advantage of the tax deferral allowed under Japanese income tax rules.