Correct. Though, in the case of the sister buying the house at less than market value, that’s not a factor - she didn’t inherit the house. If she had, it would likely have been tax free since it would likely still be worth less than the exclusion.
And, correct, that the sister would not be paying taxes on the full capital gains because of that 250K/500K exclusion on the primary residence (and if her son inherits, then it’s unlikely that any taxes will happen).
Obviously there are loads of other issues with a transfer of this sort - for example if the mother needed to go into Medicaid-funded nursing home care, it might fall within the lookback period since it was for far less than market value. Not entirely sure what happens in that case, but it wouldn’t be pretty. But there may well have been an understanding that in exchange for the cheap sale, the daughter provides care for the mother, in the home, for as long as physically possible. And of course the family dynamic (basically the residential daughter is getting the only inheritance) is unfortunate.
Your understanding meshes with mine!
To use numbers as an example: let’s say the house transferred for 150K a few years back, it was worth 750K at the time of the transfer, and it is now worth 950K. The purchaser basically saved 600K at the time of purchase. Had s/he paid market value, the profit would be 200K; instead it’s 800K.
Let’s assume the owner’s tax rate is 25%.
Sell today: your gain is 800K. Subtract out the 500K exclusion because you’ve lived in it for the required time. Your gain is 300K. You pay 75K in capital gains. You have spent 225,000 dollars, and gotten 950K back. Net profit: 725K (950K minus 150K purchase minus 75K capital gains).
If you paid full market value (750K) at the time of the transfer, your gain is 200K, with no capital gains (since it’s less than the 250/500K exclusion). Thus, your profit is also 200K.
So the purchaser still comes out ahead with the below-market purchase, just needs to be prepared to write Uncle Same a large check that year.
If the grandson inherits when the house is worth 950K, then sells the house a couple months later for 1M, the gain is 50K. I’m not sure how the “full time residence” rule applies in this case, even if he lived in the place with the mother / grandmother for the requisite number of years, since he was not the owner of the property. He’d either pay zero in gains (since 50K is less than the 250K exclusion), or the applicable tax rate on the 50K gain.
All that’s a digression from the OP’s topic. I’m avoiding work, as you can see
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