Grayscale Bitcoin Trust ETF (GBTC) 8-K Changes in Registrant's Certifying Accountant

Exhibit 16.1

March 6, 2024

Securities and Exchange Commission

100 F Street, N.E.

Washington, DC 20549

Commissioners:

We have read the statements made by Grayscale Bitcoin Trust (BTC) under Item 4.01 of its Form 8-K dated March 6, 2024. We agree with the statements concerning our Firm in such Form 8-K; we are not in a position to agree or disagree with other statements of Grayscale Bitcoin Trust (BTC) contained therein.

Very truly yours,

/s/ Marcum llp

Marcum llp