# EDGAR Filing Document

**Accession Number:** 0001998443
**File Stem:** 0001193125-25-272445
**Filing Date:** 2025-11
**Character Count:** 11752
**Document Hash:** 2364dd2b96f4ce48eee81e8d56e6740f
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001193125-25-272445.hdr.sgml**: 20251107

**ACCESSION NUMBER**: 0001193125-25-272445

**CONFORMED SUBMISSION TYPE**: SCHEDULE 13G/A

**PUBLIC DOCUMENT COUNT**: 1

**FILED AS OF DATE**: 20251107

**DATE AS OF CHANGE**: 20251107

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Waystar Holding Corp.
- **CENTRAL INDEX KEY:** 0001990354
- **STANDARD INDUSTRIAL CLASSIFICATION:** SERVICES-COMPUTER INTEGRATED SYSTEMS DESIGN [7373]
- **ORGANIZATION NAME:** 06 Technology
- **EIN:** 000000000
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13G/A
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-94694
- **FILM NUMBER:** 251463072

**BUSINESS ADDRESS:**
- **STREET 1:** 1550 DIGITAL DRIVE, #300
- **CITY:** LEHI
- **STATE:** UT
- **ZIP:** 84043
- **BUSINESS PHONE:** 844-492-9782

**MAIL ADDRESS:**
- **STREET 1:** 1550 DIGITAL DRIVE, #300
- **CITY:** LEHI
- **STATE:** UT
- **ZIP:** 84043
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Derby LuxCo S.a r.l.
- **CENTRAL INDEX KEY:** 0001998443

**ORGANIZATION NAME:**
- **EIN:** 000000000
- **STATE OF INCORPORATION:** N4
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13G/A

**BUSINESS ADDRESS:**
- **STREET 1:** 51A, BOULEVARD ROYAL
- **CITY:** GRAND DUCHY OF LUXEMBOURG
- **STATE:** N4
- **ZIP:** L-2449
- **BUSINESS PHONE:** 352 26 73 26

**MAIL ADDRESS:**
- **STREET 1:** 51A, BOULEVARD ROYAL
- **CITY:** GRAND DUCHY OF LUXEMBOURG
- **STATE:** N4
- **ZIP:** L-2449

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Derby LuxCo S.a.r.l.
- **DATE OF NAME CHANGE:** 20231023

### UNITED STATES SECURITIES AND EXCHANGE COMMISSION
**Washington, D.C. 20549**

## SCHEDULE 13G

### Under the Securities Exchange Act of 1934

**(Amendment No. 3)**

**Issuer:** Waystar Holding Corp.

**Title of Class of Securities:** Common Stock, par value $0.01 per share

**CUSIP Number:** 946784105

**Date of Event Which Requires Filing of this Statement:** 09/30/2025

**Check the appropriate box to designate the rule pursuant to which this Schedule is filed:**

- [ ] Rule 13d-1(b)

- [ ] Rule 13d-1(c)

- [x] Rule 13d-1(d)

---

| 1. | Names of Reporting Persons<br>Derby LuxCo S.a r.l. | Names of Reporting Persons<br>Derby LuxCo S.a r.l. |
|:---|:---|:---|:---|
| 2. | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [ ] (b) [ ] | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [ ] (b) [ ] |
| 3. | SEC Use Only | SEC Use Only |
| 4. | Citizenship or Place of Organization<br>N4 | Citizenship or Place of Organization<br>N4 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 5. | Sole Voting Power<br>24879437 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 6. | Shared Voting Power<br>0 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 7. | Sole Dispositive Power<br>24879437 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 8. | Shared Dispositive Power<br>0 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>24879437 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>24879437 |
| 10. | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] |
| 11. | Percent of Class Represented by Amount in Row (9)<br>14.2% | Percent of Class Represented by Amount in Row (9)<br>14.2% |
| 12. | Type of Reporting Person (See Instructions)<br>OO | Type of Reporting Person (See Instructions)<br>OO |

---

| 1. | Names of Reporting Persons<br>EQT Fund Management S.a r.l. | Names of Reporting Persons<br>EQT Fund Management S.a r.l. |
|:---|:---|:---|:---|
| 2. | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [ ] (b) [ ] | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [ ] (b) [ ] |
| 3. | SEC Use Only | SEC Use Only |
| 4. | Citizenship or Place of Organization<br>N4 | Citizenship or Place of Organization<br>N4 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 5. | Sole Voting Power<br>24879437 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 6. | Shared Voting Power<br>0 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 7. | Sole Dispositive Power<br>24879437 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 8. | Shared Dispositive Power<br>0 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>24879437 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>24879437 |
| 10. | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] |
| 11. | Percent of Class Represented by Amount in Row (9)<br>14.2% | Percent of Class Represented by Amount in Row (9)<br>14.2% |
| 12. | Type of Reporting Person (See Instructions)<br>OO | Type of Reporting Person (See Instructions)<br>OO |

---

**Item 1(a). Name of Issuer:**
Waystar Holding Corp.

**Item 1(b). Address of Issuer's Principal Executive Offices:**
1550 Digital Drive, # 300, Lehi, Utah 84043

**Item 2(a). Name of Person Filing:**
This Schedule 13G is being filed jointly by Derby LuxCo S.a r.l. ("Derby") and EQT Fund Management S.a r.l. ("EFMS") (each a "Reporting Person" and, together, the "Reporting Persons"), pursuant to an agreement of joint filing.

Several investment vehicles collectively make up the fund known as "EQT VIII." EQT VIII owns 100% of the membership interests in Derby. EFMS has exclusive responsibility for the management and control of the business and affairs of investment vehicles which constitute the majority of the total commitments to EQT VIII. EFMS is overseen by a board of not less than three individuals that acts by majority approval.

EFMS may be deemed to beneficially own the shares of Common Stock (as defined below) directly owned by Derby, but neither the filing of this Schedule 13G nor any of its contents shall be deemed to constitute an admission that EFMS is the beneficial owner of the Common Stock referred to herein for purposes of Section 13(d) of the Securities Exchange Act of 1934, as amended (the "Act"), or for any other purpose and EFMS expressly disclaims beneficial ownership of such shares. The filing of this statement should not be construed to be an admission that any of the Reporting Persons are members of a "group" for the purposes of Sections 13(d) and 13(g) of the Act.

**Item 2(b). Address of Principal Business Office:**
The address of the principal business office of Derby is:
51A, Boulevard Royal
L-2449 Luxembourg
Citizenship: Luxembourg

The address of the principal business office of EFMS is:

EQT Fund Management S.a r.l.
51A, Boulevard Royal
L-2449 Luxembourg
Citizenship: Luxembourg

**Item 2(c). Citizenship:**
Derby LuxCo S.a r.l. - Luxembourg

EQT Fund Management S.a r.l. - Luxembourg

**Item 2(d). Title of Class of Securities:**
Common Stock, par value $0.01 per share

**Item 2(e). CUSIP Number:**
946784105

**Item 3. If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:**

(a) [ ] Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o).

(b) [ ] Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c).

(c) [ ] Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c).

(d) [ ] Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8).

(e) [ ] An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);

(f) [ ] An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);

(g) [ ] A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);

(h) [ ] A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);

(i) [ ] A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);

(j) [ ] A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), if filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:

(k) [ ] Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).

**Item 4. Ownership:**

**(a) Amount beneficially owned:**

The information contained in rows 5, 6, 7, 8, 9, 10, and 11 on each of the cover pages of this Schedule 13G and the information set forth or incorporated in Item 2(a) is incorporated by reference in its entirety into this Item 4.
As of September 30, 2025, Derby directly holds 24,879,437 shares of common stock, par value $0.01 per share ("Common Stock") of Waystar Holding Corp. (the "Issuer"). EFMS may be deemed to beneficially own the Common Stock directly held by Derby.

**(b) Percent of class:**

Each of the Reporting Persons may be deemed to be the beneficial owner of the percentage of Common Stock listed on such Reporting Person's cover page. Calculations of the percentage of Common Stock beneficially owned are based on 174,667,840 shares of Common Stock outstanding as of September 30, 2025, as disclosed in the Issuer's Quarterly Report on Form 10-Q filed with the U.S. Securities and Exchange Commission on October 29, 2025.

**(c) Number of shares as to which the person has:**

**(i) Sole power to vote or to direct the vote:**

See each cover page hereof.

**(ii) Shared power to vote or to direct the vote:**

See each cover page hereof.

**(iii) Sole power to dispose or to direct the disposition of:**

See each cover page hereof.

**(iv) Shared power to dispose or to direct the disposition of:**

See each cover page hereof.

**Item 5. Ownership of Five Percent or Less of a Class.**

[ ] If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following.

**Item 6. Ownership of More than 5 Percent on Behalf of Another Person.**

The several investment vehicles that collectively constitute EQT VIII may be deemed to have the indirect right to receive or the indirect power to direct the receipt of dividends from, or the proceeds from the sale of, the Common Stock held by Derby by virtue of their ownership of Derby's membership interests. Of these vehicles, EQT VIII SCSp may be deemed to have the indirect right to receive or the indirect power to direct the receipt of dividends from, or the proceeds from the sale of, 5.0% or more of the Issuer's outstanding Common Stock.

**Item 7. Identification and Classification of the Subsidiary**

Not Applicable

**Item 8. Identification and Classification of Members of the Group**

Not Applicable

**Item 9. Notice of Dissolution of Group**

Not Applicable

**Item 10. Certification:**

—

### SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Derby LuxCo S.a r.l.**

**Date:** 11/07/2025

**By:** /s/ Tinatin Gogoladze

**Name & Title:** Tinatin Gogoladze, Manager

**EQT Fund Management S.a r.l.**

**Date:** 11/07/2025

**By:** /s/ Sara Huda

**Name & Title:** Sara Huda, Manager