Re T5’s for NON-spousal joint accounts. I can’t find where to show the % attributable to each person or to give the ID/SIN of the secondary person. What should I do?

To split your T5 with someone other than your spouse, simply report the portion that applies to you on your own tax return and provide the other joint account holder(s) with a copy of the T5 slip in order for them to report the proportionate income on their tax return.

Keep your copy of the tax slip and your explanation as to why you have not reported the full amount in your own file in case you are asked for it by CRA.