Cdn PR & US citizen w/ Cdn university employer & US

[ac12]

I have searched and read extensively and not found advice that is relevant to my situation. I hope someone can help, or at least point me to someone who can. I am a US citizen and Canadian permanent resident. I am paid by a Canadian university (with full income tax, EI, and CPP withholding), but the grant I am supported by requires me to spend a lot of time in the US with collaborators. I understand that my wages earned while in the US are taxable as US-source income on my 1040. But what are the rules for me and for my university regarding Social Security payment and withholding? Are there time limits that determine that in my case (e.g. 183 days)? I am maintaining full residential ties in Canada throughout this period. It seems to me that as a US citizen returning temporarily from abroad as a visiting researcher I somehow slip between the cracks of the exemptions set up to ease international academics. It is important to me to maintain my Canadian residency during this time for health coverage reasons, so I can't imagine that getting an exemption from paying CPP and EI, in favor of paying SS, is a good solution. And I also can't imagine that my university will be willing to get into a muddle of IRS reporting and withholding for the US. Thanks for any insights!

[nelsona]

If you are being paid by Cdn school exclusively, then there are no SS issues.

If you are being paid by US schoool, then they should be withholding FICA for you.

[ac12]

Thanks, nelsona. I also finally found the reason for this, because all the other reading I had done suggested I would be on the hook for SS taxes and I couldn't understand how I wasn't:
http://www.ssa.gov/international/Agreem ... rtificate2

[nelsona]

Again, all that is saying is that your US employer must withould SS, and your Cdn employer must withhold CCP.