21Shares Files S-1 for SEI ETF, Coinbase to Custody Assets

TLDR:

• 21Shares has filed an S-1 with the SEC to register its planned Sei-based exchange-traded fund.
• The SEI ETF will track the CF SEI-Dollar Reference Rate while Coinbase Custody safeguards all assets.
• The filing states the trust may explore staking SEI if it avoids regulatory and tax risks.
• Shares of the SEI ETF will be created and redeemed in baskets through authorized participants.
  

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A new crypto investment product is on the way. 21Shares has taken a step toward launching an exchange-traded fund tied to the Sei blockchain. 

The firm submitted a registration statement with the U.S. Securities and Exchange Commission, outlining details of its SEI ETF. Coinbase Custody will hold the digital assets on behalf of the trust. If approved, the product could bring SEI exposure to a broader set of investors.

21Shares Files SEC Registration for SEI ETF

According to the SEC filing dated August 28, 2025, 21Shares submitted an S-1 form to register its Sei ETF. The trust is structured to track the price of SEI tokens through the CF SEI-Dollar Reference Rate. It is designed as a passive vehicle, with no use of leverage or derivatives.

The filing explains that the trust will reflect SEI performance net of fees and other liabilities. The sponsor may also consider staking SEI holdings if legal and tax considerations permit. Any staking activity would be conducted through external providers or liquid staking tokens, though no final decision has been made.

The trust will not act as an investment company under the Investment Company Act of 1940. Investors will not receive the protections granted under traditional registered investment companies. Instead, the trust will operate as a grantor trust, focusing solely on SEI token exposure.

The filing states that 21Shares US LLC will serve as the sponsor of the trust, with CSC Delaware Trust Company acting as trustee. Coinbase Custody Trust Company has been appointed to safeguard the SEI tokens.

Coinbase Custody to Hold SEI Tokens for the Trust

The structure outlined in the filing shows that Coinbase Custody will serve as the SEI custodian. All tokens backing the ETF shares will be stored under its control. The custodian role covers creation and redemption flows between authorized participants and the trust.

Authorized participants will be able to create and redeem shares either in cash or in-kind with SEI. In cash transactions, a third-party counterparty selected by 21Shares will purchase SEI and deliver it to the custodian. For in-kind transactions, SEI tokens will move directly into the trust’s account.

When shares are redeemed, the trust can either sell SEI through a counterparty and return cash to the participant, or transfer SEI directly. The process is meant to keep the share price in line with the underlying SEI value.

According to the registration, the trust intends to list its shares on an exchange under a yet-to-be-announced ticker. Before launch, seed creation baskets will be acquired by an affiliate of 21Shares and delivered into the trust.

The offering is structured as continuous and will remain open for three years unless extended. Investors will be able to trade shares on the secondary market, where prices may vary from the net asset value.

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