The tax filing status as married or single is determined as of the last day of the year. So, if the divorce remains pending as of December 31st, the parties are still married for tax purposes. If the divorce is granted during the tax year, then the parties’ marital status is probably single as of December 31st. Typically, parties cannot be forced to sign a joint tax return. In most circumstances, it is usually more advantageous for parties to file a joint return than to file separately. The advice of a good CPA to give each spouse independent advice makes sense.