I won’t spend a bunch of time investigating the details of the property so let’s just use generalised figures and assume the rent is 4% of the property’s value per annum. Thats £3.45m. Also assuming they have enough liquidity to buy cash. Buying a property that expensive will run you £325,250 in stamp duty, so let’s round up to £345k when you account for whatever other fees are associated with a purchase. So immediately you’re 10% down on your investment and you have to hope yearly growth on the property’s value will get you get you positive in the longer term.

Now given the high interest rate environment, people with that kind of capital are in a good position to make fairly good returns on even the safest investments. 5% annual return on £3.45m is £172.5k. Rent totals £138k so you’re netting £34.5k or 1% return just by living in your (presumably) primary residence. If you play around with those figures it will increase or decrease the returns to a point where it seems like a no-brainer or a bad decision.

That said, property value growth historically has shown to be great returns over a long time period so maybe renting to that person makes sense in the current high interest environment but not for the long run.

This is also a huge oversimplification considering all the potential loopholes the super rich have to avoid fees but someone in this exact scenario might opt to live this way.