Thank you @HelenC12
It seems the most important thing is to prove that the investment is completely worthless. I cannot find any bankruptcy filing. But the underlying company CEO has been sentenced to jail due to fraud, and the business was no longer running. I don't find any information whether there is an asset to be liquidated. But it has been 3 years w/o any recovery. In this case, is the evidence strong enough to claim the investment is worthless?
