Grayscale Bitcoin Trust ETF expands XBX sources with Bitfinex inclusion

Rhea-AI Filing Summary

Grayscale Bitcoin Trust ETF (GBTC) filed a Form 8-K to disclose a technical but potentially beneficial change to the way its net asset value is calculated. CoinDesk Indices, Inc., the provider of the CoinDesk Bitcoin Price Index (XBX) used by the Trust, added Bitfinex as a Constituent Trading Platform effective June 22, 2025 after the venue satisfied minimum-liquidity criteria in the index provider’s scheduled quarterly review.

No existing exchanges were removed. The XBX basket now comprises seven venues: Coinbase, Kraken, Bitstamp, Crypto.com, LMAX Digital, Bullish and the newly added Bitfinex. The index provider retains discretion to add or remove platforms in future quarterly reviews, in line with the methodology outlined in GBTC’s most recent 10-K.

For shareholders this change should increase pricing depth and reduce single-venue dependency risk, but it does not alter fees, portfolio composition or the Trust’s fundamental operations. The filing contains no financial statements, earnings data or other material transactions beyond the index-constituent update.

Positive

• Addition of Bitfinex increases the XBX index’s data sources to seven exchanges, potentially enhancing liquidity and pricing accuracy for GBTC’s NAV.

Negative

• None.

Insights

Financial Analyst

TL;DR — Adding Bitfinex marginally improves index liquidity; impact neutral-to-positive.

The Trust’s NAV is derived from the XBX index, so including Bitfinex widens order-book coverage and may narrow tracking error versus global market prices. However, because GBTC already sources data from six large exchanges and the fund’s fee structure and assets remain unchanged, the addition is not expected to move earnings or cash-flow metrics. I view the disclosure as operational fine-tuning rather than a value catalyst. Regulatory risk is unchanged; Bitfinex’s legal history is now indirectly linked, but CoinDesk’s vetting criteria partially mitigate that concern.

Index Governance Specialist

TL;DR — Constituent change follows normal quarterly process; governance intact.

The filing confirms the index provider adhered to its published quarterly review schedule, adding only venues meeting objective liquidity thresholds. No methodology alterations were made, so historical comparability of index levels is preserved. Because Bitfinex’s volumes often exceed 5% of total BTC spot turnover, its inclusion should enhance representativeness. From a governance standpoint, transparent disclosure via 8-K strengthens investor confidence, but the event is not materially transformative for GBTC.

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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): June 22, 2025

Grayscale Bitcoin Trust ETF

(Exact name of Registrant as Specified in Its Charter)

Delaware			001-41906	46-7019388
(State or Other Jurisdiction of Incorporation)			(Commission File Number)	(IRS Employer Identification No.)
c/o Grayscale Investments Sponsors, LLC 290 Harbor Drive, 4th Floor
Stamford, Connecticut				06902
(Address of Principal Executive Offices)				(Zip Code)

Registrant’s Telephone Number, Including Area Code: 212 668-1427

N/A

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class		Trading Symbol(s)		Name of each exchange on which registered
Grayscale Bitcoin Trust ETF Shares		GBTC		NYSE Arca, Inc.

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 8.01. Other Events.

CoinDesk Indices, Inc. (the “Index Provider”) announced a change to the Constituent Trading Platforms used to derive the Index Price for Grayscale Bitcoin Trust ETF (the “Trust”). Effective June 22, 2025, the Index Provider added Bitfinex to the CoinDesk Bitcoin Price Index (XBX) (the “Index”) due to the trading platform meeting the Index Provider’s minimum liquidity requirement, and did not remove any Constituent Trading Platforms as part of its scheduled quarterly review. As of the date of this current report, the Digital Asset Trading Platforms included in the Index are Coinbase, Kraken, Bitstamp, Crypto.com, LMAX Digital, Bullish and Bitfinex.

The Index Provider may change the trading venues that are used to calculate the Index Price, or otherwise change the way in which an Index Price is calculated, at any time. The Index Provider has scheduled quarterly reviews, in which it may add or remove Constituent Trading Platforms that satisfy or fail the criteria described in “Item 1. Business—Overview of the Bitcoin Industry and Market—Bitcoin Value—The Index and the Index Price” in the Trust’s Annual Report on Form 10-K for the year ended December 31, 2024, as filed with the Securities and Exchange Commission on February 27, 2025.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

			Grayscale Investments Sponsors, LLC, as Sponsor of Grayscale Bitcoin Trust ETF
Date:	June 25, 2025	By:	/s/ Edward McGee
			Name: Edward McGee Title: Chief Financial Officer*

* The Registrant is a trust and the identified person signing this report is signing in their capacity as an authorized officer of Grayscale Investments Sponsors, LLC, the Sponsor of the Registrant.

FAQ

What material event did GBTC report in its June 22 2025 Form 8-K?

The Trust disclosed that Bitfinex was added to the CoinDesk Bitcoin Price Index (XBX) used to value GBTC.

Which exchange was added to the CoinDesk XBX index for GBTC?

Bitfinex was added effective June 22 2025 after meeting liquidity requirements.

How many exchanges now make up the XBX index after the update?

The index now sources prices from seven exchanges: Coinbase, Kraken, Bitstamp, Crypto.com, LMAX Digital, Bullish and Bitfinex.

Were any trading platforms removed in this quarterly review?

No. The index provider did not remove any Constituent Trading Platforms during the review.

Can the index provider change constituents again in the future?

Yes. CoinDesk Indices conducts scheduled quarterly reviews and may add or remove platforms that meet or fail its criteria.

Does the change affect GBTC’s fees or portfolio structure?

No. The filing reports no changes to fees, portfolio holdings, or other operational aspects of the Trust.