Source deductions of income tax are withheld from your income in order to spread all or part of your income tax payable over the year. 

At your request, the amount withheld can be reduced to take into account any tax deductions to which you may be entitled (such as the basic amount).

However, you can receive income from more than one source, for example:

• the Old Age Security pension
• Québec Pension Plan benefits
• benefits from a private pension plan

In this case, it may be in your interest to request a reduction with regard to only one source of income. Otherwise, your source deductions may not cover all of your income tax payable for the year and you may be obliged to pay an additional amount when you complete your income tax return.