You said: << I believe ChatGPT was correct relative to the LTCLoss.
It boils down to Proceeds minus Basis. In your case, all is prorated if half is sold.
Long‑term capital loss offsets other LT gains. >>
I find that a bit unclear. The issue was if some of my LTCG is subject to NIIT and some of it is not, then how do I determine how much long-term capital loss is to be used in the NIIT calculation. Chatgpt claims it can all be used in the NIIT calculation which seemed great, but odd, to me since only a small portion of the LTCG needed to be included in the NIIT assessment. Thanks. I ended up selling all of the stock, so so much for prorating in the other sense but the NIIT versus non_NIIT portion pro ration, if any, question was still relevant. Yes, I had my hands full. Chatgpt is not very good at handling a problem this intricate, I found, FWIW.
