[8-K] Grayscale Stellar Lumens Trust (XLM) Reports Material Event

Rhea-AI Filing Summary

The filing describes the Index methodology used to price the Grayscale Stellar Lumens Trust (GXLM). The Index is a volume-weighted, real-time USD-denominated price that selects and weights constituent trading platforms by trailing 24-hour liquidity and applies FX normalization for stablecoin pairs. The methodology includes outlier detection (prices ±5% versus the latest Index are excluded), an inactivity adjustment that progressively de-weights a platform to near-zero within 25 minutes of no activity, and procedures to penalize stale data. The Index Provider applies qualitative and quantitative screens to choose constituent platforms and seeks manipulation resistance. If the primary real-time rate is unavailable, the Sponsor uses a Secondary Index, then a Tertiary Pricing Option, and finally the Sponsor’s good-faith estimate; the Sponsor’s good-faith assessments have no predefined criteria and are made at its sole discretion.

Positive

• Volume-weighted, real-time pricing that weights constituent trading platforms by trailing 24-hour liquidity
• FX normalization for stablecoin-USD pairs so all activity is denominated in USD
• Outlier detection (+/-5%) and inactivity de-weighting (progresses to ~0 in 25 minutes) to reduce noise and stale data
• Multi-tiered fallback pricing using a Secondary Index and a Tertiary Pricing Option to preserve continuity

Negative

• Sponsor discretion without predefined criteria for ‘‘good faith’’ determinations of Index Price introduces subjective judgment at the final fallback
• No quantitative thresholds provided for selecting or removing Constituent Trading Platforms beyond qualitative factors described

Insights

Financial Analyst

TL;DR: The methodology prioritizes liquidity and real-time volume-weighted pricing with multi-level fallbacks and explicit outlier/inactivity controls.

The Index framework emphasizes execution realism by weighting trading platforms by trailing 24-hour volume and applying FX normalization to express prices in USD. The +/-5% outlier filter and gradual de-weighting for inactive platforms (effectively zero after 25 minutes) are operational controls that reduce short-lived noise. Multi-tiered fallbacks — Secondary Index, Tertiary Pricing Option, then Sponsor estimate — provide continuity, though the Sponsor’s discretionary good-faith standard lacks objective criteria. For investors, the approach seeks robust price discovery but retains subjectivity at the final pricing stage.

Index Specialist

TL;DR: Design is consistent with industry index practices: volume weighting, variance-based weighting, outlier removal, and staged fallback pricing.

The algorithm’s weighted-median techniques (half volume, half inverse price variance) and volume-based platform weighting align with practices to reduce influence of high-variance venues. The outlier rule (+/-5%) and inactivity penalty reduce susceptibility to errant prints and stale feeds. The reliance on a Secondary Index Provider and a tertiary market feed is appropriate, but the methodology explicitly grants the Sponsor unilateral discretion to determine a ‘‘good faith’’ price without predefined criteria, which introduces non-algorithmic judgment at the final step.

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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): September 26, 2025

Grayscale Stellar Lumens Trust (XLM)

(Exact name of Registrant as Specified in Its Charter)

Delaware			000-56434	83-6545098
(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(g) of the Act:

Title of each class		Trading Symbol(s)		Name of each exchange on which registered
Grayscale Stellar Lumens Trust (XLM) Shares		GXLM		N/A

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.

Prior to October 1, 2025, Grayscale Stellar Lumens Trust (XLM) (the “Trust”) valued the XLM held by the Trust for operational purposes by reference to the CoinDesk Stellar Lumens Index (XLMX). As of October 1, 2025, the Index will be the CoinDesk XLM CCIXber Reference Rate. As of October 1, 2025, the NAV and NAV per Share of the Trust will be calculated using the Index Price based on the CoinDesk XLM CCIXber Reference Rate. Prior to October 1, 2025, references to the “Index” in the Trust's filings with the SEC refer to the CoinDesk Stellar Lumens Index (XLMX). From and after October 1, 2025, references to the “Index” in the Trust's filings with the SEC will be to the CoinDesk XLM CCIXber Reference Rate.

Capitalized terms used but not defined herein have the meanings ascribed to them in the Trust’s Annual Report on Form 10-K for the fiscal year ended September 30, 2024.

Constituent Trading Platform Selection

Under the CCIXber methodology, The Digital Asset Trading Platforms to be included in the Index are selected by the Index Provider utilizing a methodology that is guided by the International Organization of Securities Commissions (“IOSCO”) principles for financial benchmarks. For a trading platform to become a Constituent Trading Platform, it must satisfy the criteria listed below (the “Inclusion Criteria”):

•No evidence in the past 12 months of trading restrictions on individuals or entities that would otherwise meet the trading platform’s eligibility requirements to trade;

•No evidence in the past 12 months of undisclosed restrictions on deposits or withdrawals from user accounts;

•Real-time price discovery;

•Limited or no capital controls;

•Transparent ownership including a publicly-owned ownership entity;

•Publicly available language and policies addressing legal and regulatory compliance, including KYC, AML and other policies designed to comply with relevant regulations that might apply to it;

•Offer programmatic spot trading of the trading pair and reliably publish trade prices and volumes on a real-time basis through Rest and Websocket APIs;

•Is a centralized spot trading platform ranked BB or higher in the Index Provider’s latest published Trading Platform Benchmark report; and

•Is not classified as an Excluded Trading Platform as defined in the Index Provider’s Digital Asset Indices Policy Methodology.

All trading platforms that meet these Inclusion Criteria will be assigned to a “Trading Platform Category” as defined by the additional criteria below, and at least one Category 1 Trading Platform must be included in each Index Price.

•A “Category 1 Trading Platform” is a trading platform:

oLicensed and/or able to serve investors, retail or professional, in the U.S.; and

oThat maintains sufficient USD or USDC liquidity relative to the size of the listed assets.

•A “Category 2 Trading Platform” is a trading platform:

oLicensed (including in-principal licensure) and/or able to serve investors, retail or professional, in one or more of the following jurisdictions: United Kingdom, European Union, Hong Kong, Singapore; and

oThat maintains sufficient USD or USDC liquidity relative to the size of the listed assets.

A Digital Asset Trading Platform is removed from the Constituent Trading Platforms when it no longer satisfies the Inclusion Criteria. The Index Provider does not currently include data from over-the-counter markets or derivatives platforms among the Constituent Trading Platforms. Over-the-counter data is not currently included because of the potential for trades to include a significant premium or discount paid for larger liquidity, which creates an uneven comparison relative to more active markets. There is also a higher potential for over-the-counter transactions to not be arms-length, and thus not be representative of a true market price. XLM derivative markets are also not currently included. While the Index Provider has no plans to include data from over-the-counter markets or derivative platforms at this time, the Index Provider will consider IOSCO principles for financial benchmarks, the management of trading venues of XLM derivatives and the aforementioned Inclusion Criteria when considering whether to include over-the-counter or derivative platform data in the future.

The Index Provider and the Sponsor have entered into the index license agreement, dated as of February 1, 2022 (as amended, the “Index License Agreement”), governing the Sponsor’s use of the Index Price. Pursuant to the terms of the Index License Agreement, the Index Provider may adjust the calculation methodology for the Index Price without notice to, or consent of, the Trust or its shareholders. The Index Provider may decide to change the calculation methodology to maintain the integrity of the Index Price calculation should it identify or become aware of previously unknown variables or issues with the existing methodology that it believes could materially impact its performance and/or reliability. The Index Provider has sole discretion over the determination of the Index Price and may change the methodologies for determining the Index Price from time to time. Shareholders will be notified of any material changes to the calculation methodology or the Index Price in the Trust’s current reports and will be notified of all other changes that the Sponsor considers significant in the Trust’s periodic or current reports. The Sponsor will determine the materiality of any changes to the Index Price on a case-by-case basis, in consultation with external counsel.

The Index Provider may change the trading venues that are used to calculate the Index or otherwise change the way in which the Index is calculated at any time. For example, the Index Provider has scheduled quarterly reviews in which it may add or remove Constituent Trading Platforms that satisfy or fail the Inclusion Criteria. The Index Provider does not have any obligation to consider the interests of the Sponsor, the Trust, the shareholders, or anyone else in connection with such changes. While the Index Provider is not required to publicize or explain the changes or to alert the Sponsor to such changes, it has historically notified the Trust of any material changes to the Constituent Trading Platforms, including any additions or removals of the Constituent Trading Platforms, in addition to issuing press releases in connection with the same. The Sponsor will notify investors of any such material event by filing a current report on Form 8-K. Although the Index methodology is designed to operate without any manual intervention, rare events would justify manual intervention. Intervention of this kind would be in response to non-market-related events, such as the halting of deposits or withdrawals of funds on a Digital Asset Trading Platform, the unannounced closure of operations on a Digital Asset Trading Platform, insolvency or the compromise of user funds. In the event that such an intervention is necessary, the Index Provider would issue a public announcement through its website, API and other established communication channels with its clients.

Determination of the Index Price

The Index, as will be reflected by the CoinDesk XLM CCIXber Reference Rate, for XLM is calculated through the application of an algorithm to the price of XLM on the Constituent Trading Platforms calculated every 5 seconds over a 24-hour period. The Index’s algorithm is expected to reflect a five-pronged methodology to calculate the Index Price from the Constituent Trading Platforms for XLM:

•Volume Weighting: Constituent Trading Platforms with greater liquidity receive a higher weighting in each Index, increasing the ability to execute against (i.e., replicate) the Index in the underlying spot markets. The Index methodology is a volume-weighted real-time price where each Constituent Trading Platform is weighted based on its trailing 24-hour volume.

•FX Conversion: The Index algorithm utilizes a volume-weighted real-time FX conversion rate for any trading activity for the relevant Stablecoin-USD pair. This normalizes all trading activity to USD denomination.

•Outlier Detection Factor: The Index algorithm excludes trade data and price(s) deemed to be an outlier relative to the most recently calculated Index.

•Outlier Detection Factor: The Index algorithm penalizes stale activity from any given Constituent Trading Platform. When a Constituent Trading Platform does not have recent trading data, the outdated prices and their contribution to the Index calculation are gradually reduced until they are de-weighted to 0.1%. Similarly, once trading activity at a Constituent Trading Platform resumes, the corresponding weighting for that Constituent Trading Platform will no longer be penalized.

•Manipulation Resistance: In an effort to determine and prioritize the most significant Constituent Trading Platforms (i.e., those that are likely to have the most impact on price discovery) for a given asset, the Index Provider conducts a Constituent Trading Platform selection and review process, which seeks to identify the highest-ranking Constituent Trading Platforms based on both qualitative and quantitative factors. The qualitative review includes legal and regulation, data provision, security, trade monitoring, market quality, and negative events policy, among others. The quantitative review includes review of trading activity for the asset on the given Constituent Trading Platform.

The Index Provider re-evaluates the weighting algorithm on a periodic basis, but maintains discretion to change the way in which an Index Price is calculated based on its periodic review or in extreme circumstances. The exact methodology to calculate the Index Price is not publicly available. Still, the Index is designed to limit exposure to trading or price distortion of any individual Digital Asset Trading Platform that experiences periods of unusual activity or limited liquidity by discounting, in real-time, anomalous price movements at individual Digital Asset Trading Platforms.

The Sponsor believes the Index Provider’s selection process for Constituent Trading Platforms as well as the methodology of the Index Price’s algorithm provides a more accurate picture of XLM price movements than a simple average of Digital Asset Trading Platform spot prices, and that the weighting of XLM prices on the Constituent Trading Platforms limits the inclusion of data that is

influenced by temporary price dislocations that may result from technical problems, limited liquidity or fraudulent activity elsewhere in the XLM spot market.

By referencing multiple trading venues and weighting them based on trade activity, the Sponsor believes that the impact of any potential fraud, manipulation or anomalous trading activity occurring on any single venue is reduced.

If the Index Price becomes unavailable, or if the Sponsor determines in good faith that such Index Price does not reflect an accurate price for XLM, then the Sponsor will, on a best efforts basis, contact the Index Provider to obtain the Index Price directly from the Index Provider. If after such contact such Index Price remains unavailable or the Sponsor continues to believe in good faith that such Index Price does not reflect an accurate price for the XLM , then the Sponsor will employ a cascading set of rules to determine the Index Price, as described below in “—Determination of the Index Price When Index Price is Unavailable.”

The Trust values its XLM for operational purposes by reference to the Index Price. The Index Price is the value of an XLM as represented by the Index, calculated at 4:00 p.m., New York time, on each business day.

Illustrative Example

For the purposes of illustration, outlined below are examples of how the attributes that impact weighting and adjustments in the aforementioned methodology may be utilized to generate the Index Price for a digital asset.

For example, Constituent Trading Platforms used to calculate the Index Price of the digital asset may include trading platforms such as Crypto.com, Kraken, LMAX Digital and Bitstamp by Robinhood.

The Index Price algorithm, as described above, is designed to account for manipulation at the outset by only including data from executed trades on Constituent Trading Platforms that charge trading fees. Then, the below-listed elements may impact the weighting of the Constituent Trading Platforms on the Index Price as follows:

•Volume Weighting: Each Constituent Trading Platform will be weighted to appropriately reflect the trading volume share of the Constituent Trading Platform relative to all the Constituent Trading Platforms during this same period. For example, an average hourly weighting of 67.06%, 14.57%, 11.88%, and 6.49% for Crypto.com, Kraken, LMAX Digital and Bitstamp by Robinhood, respectively, would represent each Constituent Trading Platform’s share of trading volume during the same period.

•Inactivity Adjustment: Assume that a Constituent Trading Platform represented a 14% weighting on the Index Price of the digital asset, which is based on the per-second calculations of its trading volume and price-variance relative to the cohort of Constituent Trading Platforms included in such Index, and then went offline for approximately two hours. The index algorithm would automatically recognize inactivity and start de-weighting the Constituent Trading Platform at the 5-minute mark and continue to do so with each additional 5-minute period of inactivity until its influence was effectively zero, 25 minutes after becoming inactive. As soon as trading activity resumed at the Constituent Trading Platform, the index algorithm would re-weight it to the appropriate weighting based on trading volume and price-variance relative to the cohort of Constituent Trading Platforms included in the Index.

•Price Outlier Detection: New traded prices from Constituent Trading Platforms are compared to the latest calculated Index Price. If a new traded price deviates by +/- 5% from the latest calculated Index Price, it will be considered an outlier and will not be used in the calculation of the Index Price until such time as a majority of the Constituent Trading Platforms are similarly considered outlier prices. In that case, the new prices will be used to calculate the Index Price. For example, if the Index Price is $10 and there is a new trade price of $11 from Constituent Trading Platform X, the price of $11 will be considered an outlier and will not be used. However, if the most recent prices on a majority of the Constituent Trading Platforms are aligned with the price of $11, then these prices will no longer be considered outliers and will be used to calculate the new Index Price.

Determination of the Index Price When Index Price is Unavailable

The Sponsor uses the following cascading set of rules to calculate the Index Price. For the avoidance of doubt, the Sponsor will employ the below rules sequentially and in the order as presented below, should one or more specific rule(s) fail:

1.Index Price = The price set by the Index as of 4:00 p.m., New York time, on the valuation date. If the Index becomes unavailable, or if the Sponsor determines in good faith that the Index does not reflect an accurate price, then the Sponsor will, on a best efforts basis, contact the Index Provider to obtain the Index Price directly from the Index Provider. If after such contact the Index remains unavailable or the Sponsor continues to believe in good faith that the Index does not reflect an accurate price, then the Sponsor will employ the next rule to determine the Index Price. There are no predefined criteria to make a good faith assessment and it will be made by the Sponsor in its sole discretion.

2.Index Price = The price set by Coin Metrics Real-Time Rate (the “Secondary Index”) as of 4:00 p.m., New York time, on the valuation date (the “Secondary Index Price”). The Secondary Index Price is a real-time reference rate price, calculated using trade data from constituent markets selected by Coin Metrics Inc. (the “Secondary Index Provider”). The Secondary Index Price is calculated by applying weighted-median techniques to such trade data where half the weight is derived from the trading volume on each constituent market and half is derived from inverse price variance, where a constituent market with high price variance as a result of outliers or market anomalies compared to other constituent markets is assigned a smaller weight. The Secondary Index Provider and the Sponsor have entered into the master services agreement, dated as of August 4, 2020, and order forms thereunder, pursuant to which the Sponsor may obtain and use the Secondary Index and the Secondary Index Price from the Secondary Index Provider. If the Secondary Index becomes unavailable, or if the Sponsor determines in good faith that the Secondary Index does not reflect an accurate price, then the Sponsor will, on a best efforts basis, contact the Secondary Index Provider to obtain the Secondary Index Price directly from the Secondary Index Provider. If after such contact the Secondary Index remains unavailable or the Sponsor continues to believe in good faith that the Secondary Index does not reflect an accurate price, then the Sponsor will employ the next rule to determine the Index Price. There are no predefined criteria to make a good faith assessment and it will be made by the Sponsor in its sole discretion.

3.Index Price = The price set by the Trust’s principal market (the “Tertiary Pricing Option”) as of 4:00 p.m., New York time, on the valuation date. The Tertiary Pricing Option is a spot price derived from the principal market’s public data feed that is believed to be consistently publishing pricing information as of 4:00 p.m., New York time, and is provided to the Sponsor via an application programming interface. If the Tertiary Pricing Option becomes unavailable, or if the Sponsor determines in good faith that the Tertiary Pricing Option does not reflect an accurate price, then the Sponsor will, on a best efforts basis, contact the Tertiary Pricing Provider to obtain the Tertiary Pricing Option directly from the Tertiary Pricing Provider. If after such contact the Tertiary Pricing Option remains unavailable after such contact or the Sponsor continues to believe in good faith that the Tertiary Pricing Option does not reflect an accurate price, then the Sponsor will employ the next rule to determine the Index Price. There are no predefined criteria to make a good faith assessment and it will be made by the Sponsor in its sole discretion.

4.Index Price = The Sponsor will use its best judgment to determine a good faith estimate of the Index Price. There are no predefined criteria to make a good faith assessment and it will be made by the Sponsor in its sole discretion.

In the event of a fork, the Index Provider may calculate the Index Price based on a digital asset that the Sponsor does not believe to be the appropriate asset that is held by the Trust. In this event, the Sponsor has full discretion to use a different index provider or calculate the Index Price itself using its best judgment.

The Sponsor may, in its sole discretion, select a different index provider, select a different index price provided by the Index Provider, calculate the Index Price by using the cascading set of rules set forth above, or change the cascading set of rules set forth above at any time. The Sponsor will provide notice of any such changes in the Trust’s periodic or current reports and, if the Sponsor makes such a change other than on an ad hoc or temporary basis, will file a proposed rule change with the SEC.

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 Stellar Lumens Trust (XLM)
Date:	September 26, 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

How is the GXLM Index Price determined?

The Index is a volume-weighted real-time USD price that weights constituent trading platforms by trailing 24-hour volume and applies FX conversion for stablecoin-USD pairs.

What outlier rule does the methodology use for trade prices?

Prices that deviate +/-5% from the latest Index Price are treated as outliers and excluded until a majority of constituent platforms report similar prices.

How does the Index handle a trading platform that goes offline?

Inactivity de-weighting begins after 5 minutes and continues each 5-minute period until the platform’s influence is effectively zero after about 25 minutes; weight is restored when activity resumes.

What fallback options exist if the primary Index source is unavailable?

First the Secondary Index (Coin Metrics Real-Time Rate), then the Tertiary Pricing Option (principal market feed), and finally the Sponsor’s good-faith estimate.

What are Category 1 and Category 2 trading platforms?

Category 1 platforms can serve U.S. investors and maintain sufficient USD/USDC liquidity; Category 2 platforms are licensed or able to serve investors in the UK, EU, Hong Kong, or Singapore and maintain sufficient USD/USDC liquidity.