21Shares has filed an S-1 document with the U.S. Securities and Exchange Commission (SEC) to launch the 21Shares Sei ETF, which will track the price of the SEI token. The ETF will not utilize leverage or derivatives, and the SEI tokens will be held in custody by Coinbase Custody. Shares of the ETF are expected to be listed on an exchange, with authorized participants able to subscribe and redeem using cash or physical assets.