I don't know.

When you actually "earn" status, then yes of course, you lose XPs in the process.

I think I saw at least one person report, over in the thread in the BA forum, that they received an upgrade but also retained their XPs; however, I can't find the post back, and I'm not sure that that is actually such a good thing. Instead of getting a full year at the new matched level, you would only apparently have however long until your currently-running membership year ends. So, while you might "gain" something in retaining your year-to-date XPs, you "lose" in that you now have a much higher target (you've been upgraded in status, so your next hurdle is correspondingly much higher) and you have less time to reach it.

(Of course, another option is that they give you the full year to requalify - and also don't take any of the XPs. That would be extremely generous. And maybe that is what the person posting in the BA thread actually experienced)

I invite you to browse that thread to see if you can find the report, and possibly reach out to the member involved. In any case, please post any further queries relating to the BA angle in that thread.

Good luck!

https://www.flyertalk.com/forum/brit...tus-match.html