In a new court filing, digital asset management company Grayscale is calling out the U.S. securities regulator for its "illogical" and "fundamentally unreasonable" argument against the approval of a spot bitcoin exchange-traded fund (ETF).

The document filed on Friday was in response to the Securities and Exchange Commission's (SEC) December defense of its decision to reject Grayscale Investment’s application to convert its flagship Grayscale Bitcoin Trust (GBTC) into a spot bitcoin ETF.

On June 29, 2022, the same day that the SEC rejected its application, Grayscale filed suit requesting the U.S. Court of Appeals for the District of Columbia Circuit to review the order. Although a number of industry players rallied around Grayscale, the SEC stood by its call to reject the conversion, which would have allowed users to buy bitcoin on a standard stock exchange at current prices.