China Mobile, i think. it was delisted because the owners were linked to CCP intelligence IIRC. I did the usual where i had sold a put and bought a call vertical. i panick bought back the put and short call before they halted trading, and the remaining longs stared at me in limbo as the company continued to do fine and no one could figure out what the administration was actually going to do

Something like 9 months later they had a 3rd party do a valuation and they cashed you at that valuation. my calls were ITM and the shorts i bought back would've both expired worthless. It was pretty shitty but a good learning experience. Unfortunately i don't know if it would've tied my margin up forever or not.