The Grayscale Bitcoin Trust ETF (GBTC) is lower by about 11%...

...decoupling from the underlying bitcoin price...

The reason for the drop appears to be a distribution event where the GBTC is being used to seed a mini Bitcoin trust:

Grayscale Investments®, the world's largest crypto asset manager*, offering more than 20 crypto investment products, previously announced that it has set a record date of July 30, 2024 (the "Record Date") for the initial creation and distribution of shares of Grayscale Bitcoin Mini Trust (the "BTC Trust") to shareholders of Grayscale Bitcoin Trust (Ticker: GBTC) ("GBTC") (referred to as the "Initial Distribution").

Grayscale also previously announced an intention to list Grayscale Bitcoin Mini Trust on NYSE Arca, subject to required regulatory approvals, under the ticker symbol "BTC."

Today, Grayscale is confirming that from and after July 30, 2024, anyone who purchases GBTC shares will not be entitled to receive BTC shares in the Initial Distribution.

Additionally, Grayscale currently expects the Initial Distribution Date to be July 31, 2024, following (i) the filing and effectiveness of the BTC Trust's registration statement on Form 8-A to register the BTC Shares under the Exchange Act, (ii) the effectiveness of the BTC Trust's registration statement on Form S-1 (Registration No. 333-277837) under the Securities Act, and (iii) the BTC Shares having been approved for listing on NYSE Arca.