Ownership and income tax: implied trust: constructive trust - size of interest
If evidence of a common intention is found, and detriment is established, the next question is the size of the beneficial interest to which the claimant is entitled.
This is based on the facts. In establishing this in (non-tax) Court cases, the Court has not been confined to looking at contributions to the purchase price. They may take into account express agreements between the parties or give credit to one party for improvements to the property that they have funded.