Grayscale Investments, a cryptocurrency asset management company, said the U.S. Securities and Exchange Commission (SEC) has filed its first legal brief in response to Grayscale's previous lawsuit over the denial of an application to convert GBTC into a spot bitcoin ETF. . In a 73-page response brief, the SEC argued that its rejection was "reasonable, justified, and supported by substantial evidence." The SEC said that while two CME bitcoin futures ETPs had already been approved, there was no contradiction in the SEC’s disapproval of Grayscale’s spot ETP. The SEC said that futures and spot bitcoin funds are "fundamentally different products." In this regard, Grayscale published an article to respond and reiterate its previous views: 1. The SEC has created an unfair playing field for investors by approving Bitcoin futures-based ETFs while continuously rejecting spot Bitcoin ETFs. 2. The SEC failed to comply with the Administrative Procedure Act (APA) and the Securities Exchange Act of 1934 when it approved a bitcoin futures ETF but rejected a spot bitcoin ETF. 3. The SEC did not clarify the basis for its different treatment of spot bitcoin ETFs and bitcoin futures ETFs, in fact, they created a "significant market test" and did not treat each product type consistently. Grayscale said its next briefing will be due by January 13 next year, with the final briefing due by February 3.