Public trading of Sinovac Shares on NASDAQ has been halted since February 22, 2019. If you are stuck holding shares and want to cash out, you can sell them to Alternative Liquidity Capital.
New tender offer filed with the SEC today:
https://www.sec.gov/Archives/edgar/data/1870412/000187041224000001/0001870412-24-000001-index.htm
Alternative Liquidity’s letter to investors is here:
https://www.sec.gov/Archives/edgar/data/1870412/000187041224000001/0001870412-24-000001-index.htm
Alternative Liquidity will also purchase other delisted stocks: