FAQ: Why is the Platform Not Splitting Non-Registered Contributions Evenly?

The platform will try to split income and reduce tax as much as possible, and it may try to put non-registered investments in the name of the lower-income spouse first (up to the limit of their own income sources). This may result in an uneven split of contributions.

You can always use the override functionality to set specific contributions goals in Planning > Projections > Table, but check that your overrides actually improve the overall estate value and tax payments.