If one spouse uses “married filing separately” as the filing status, the other spouse must also use this filing status. The other spouse must file if his/her gross income is more than a set amount. For 2017 returns, this amount is $4,050.
Shifting income to a later year, such as where you defer taxable interest to the following year by purchasing a T-bill or savings certificate maturing after the end of the current year. Investments in qualified retirement plans provide tax deferral.