Is it mandatory to activate CPP in US

[dogwood]

I am short by a couple of years of the 30 years of contributing to Social Security. I do get forms yearly from SS asking if I am eligible for any other pensions from foreign countries. Does Social Security require me to apply for CPP so that they can reduct my benefit accordingly because of Windfall Provision? Or can I refuse to do that. I just don't want to deal with the CPP system.

[nelsona]

WEP will never wipe out all your CPP, especially with 28 years of SS contributions, so not taking it not really justified. If you do not need the income, you could wait until you hit 70. It really is free money to you.

FYI. WEP is only determined the first month in which you collect BOTH SS and CPP. OAS is not touched by OAS.

CPP and OAS are taxable only in US, and treated like SS. Paid to you in USD. You do not even have to file a return in Canada.