GST must have been attributed
A decreasing adjustment for a bad debt can arise in respect of a supply if either :
When do you account for the adjustment?
You attribute an adjustment to the tax period in which you become aware of it. Therefore, you attribute the decreasing adjustment to the tax period in which you write off the debt. If the debt has been overdue for 12 months or more, you attribute the decreasing adjustment to the tax period in which you become aware that the debt had become overdue for 12 months or more.
Remember that a debt, in most circumstances, should be outstanding for at least 12 months before it should be declared as ’bad’.
How much GST is adjusted?
For a wholly taxable supply, the amount of the decreasing adjustment is 1/11 of the amount that has been written off as bad, or is overdue for 12 months or more.