Foreign property rental income transfer to my wife in the UK tax return

Hello, My wife and I jointly own a foreign property in the US (the mortgage is only under my name) and we rent it out since 2019 and receive foreign rental income. We have been UK tax residents since 2019-20 and live in Scotland. In the past few years, we used the self-assessment and added the foreign rental income into our self-assessment form in the 50-50 split. We also do the US tax return every US tax year. A couple of questions here: 1. Can I use Form 17 to transfer 50% of my foreign rental income to my wife? I believe this can be done for the UK property along with the declaration of trust and there are many examples in the forum. And I wonder if this can apply to foreign properties in the US? 2. If we can use Form 17, then can we adjust it back to the 2019-20 tax year? 3. If we cannot use Form 17, what can we do to transfer the foreign rental income? Thanks

Hi qzhao24,
A form 17 is an election where property is held jointlly by a husband and wife where a 50/50 split is not apprpriate because other factors mean this is not accurate and the property is in fact owned in unequal proportions and should be based on the individual facts.  
A form 17 also cannot be backdated.
Please see our trust manual regarding this  TSEM9842 - Property held jointly by married couples or civil partners: Form 17 rule  
So if the property is jointly owned then the default position is a 50/50 automatic split.
However this would not appear to be the case here if the mortgage is not in joint names but we do not know the full circumatances so cannot comment further regarding this.
As the property is based in the US we also cannot advise further regarding the possible transfer of the asset as that could be impacted on by US tax legislation.
Thank you.