If your net income for 2009 exceeds $66,335 then your OAS benefits will be clawed back and you will have to pay back part, or all, of your pension. In addition, your pension for 2010 will be reduced by the same amount.

But what if your income exceeded this threshold because of a one-time occurrence? For example, you sold a cottage and the taxable capital gains made your income very high for this year only. Your OAS benefits for 2010 would still be eliminated and you would have to wait until 2011 to recoup this amount. In order to avoid this, you can file Form T1213 (OAS) which allows you to receive your pension in 2010 rather than waiting to recover this amount a year later.