# EDGAR Filing Document

**Accession Number:** 0001990354
**File Stem:** 0001410578-25-002023
**Filing Date:** 2025-9
**Character Count:** 229059
**Document Hash:** 527afcef5e4f77a8a5d45b1fb8f681f4
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001410578-25-002023.hdr.sgml**: 20250911

**ACCESSION NUMBER**: 0001410578-25-002023

**CONFORMED SUBMISSION TYPE**: 424B7

**PUBLIC DOCUMENT COUNT**: 12

**FILED AS OF DATE**: 20250911

**DATE AS OF CHANGE**: 20250911

**FILER**: 

**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:** 424B7
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 333-288662
- **FILM NUMBER:** 251308564

**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

[**TABLE OF CONTENTS**](#TOC)

#### Filed Pursuant to Rule 424(b)(7)

#### Registration No. 333-288662

#### PROSPECTUS SUPPLEMENT (To Prospectus dated July 14, 2025)

### 18,000,000 Shares
![[MISSING IMAGE: lg_waystar-4c.jpg]](lg_waystar-4c.jpg)

### Common Stock
This is a public offering of 18,000,000 shares of common stock of Waystar Holding Corp. The selling stockholders identified in this prospectus supplement are offering 18,000,000 shares of common stock. We are not selling any shares of common stock under this prospectus supplement and will not receive any proceeds from the sale of the shares by the selling stockholders.

Our common stock is listed on the Nasdaq Global Select Market ("Nasdaq") under the symbol "WAY." On September 10, 2025, the last reported sale price of our common stock on Nasdaq was $40.50 per share.

 ***Investing in our common stock involves risks. See "Risk Factors" beginning on page [S-5](#sRIFA) of this prospectus supplement and in the reports we file with the U.S. Securities and Exchange Commission (the "SEC") pursuant to the Securities Exchange Act of 1934, as amended (the "Exchange Act"), incorporated by reference in this prospectus supplement or the accompanying prospectus, to read about factors you should consider before buying shares of our common stock.***

 **Neither the SEC nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus supplement or the accompanying prospectus. Any representation to the contrary is a criminal offense.** 

---

| | | |
|:---|:---|:---|
| | **Per Share**  | **Total**  |
| Public offering price  | $39.40 | $709200000 |
| Underwriting discount  | $0.19 | $3420000 |
| Proceeds, before expenses, to the selling stockholders<sup>(1)</sup>  | $39.21 | $705780000 |

---

(1) See "Underwriting" for a description of the compensation payable to the underwriter.

The underwriter expects to deliver the shares against payment in New York, New York on or about September 12, 2025.

### J.P. Morgan

#### Prospectus Supplement dated September 10, 2025.

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#### **TABLE OF CONTENTS**

#### Prospectus Supplement

---

| | |
|:---|:---|
| | **Page**  |
| [Prospectus Supplement Summary](#sPSS)  | [S-1](#sPSS) |
| [Risk Factors](#sRIFA)  | [S-5](#sRIFA) |
| [Special Note Regarding Forward-Looking Statements](#sSNRF)  | [S-11](#sSNRF) |
| [Use of Proceeds](#sUOP)  | [S-14](#sUOP) |
| [Selling Stockholders](#sSEST)  | [S-15](#sSEST) |
| [Underwriting](#sUND)  | [S-17](#sUND) |
| [Legal Matters](#sLEMA)  | [S-25](#sLEMA) |
| [Experts](#sEXP)  | [S-25](#sEXP) |
| [Where You Can Find More Information](#sWYCF)  | [S-25](#sWYCF) |
| [Incorporation by Reference](#sIBR)  | [S-25](#sIBR) |

---

#### Prospectus

---

| | |
|:---|:---|
| | **Page**  |
| [Prospectus Summary](#tPRSU)  | [1](#tPRSU) |
| [Risk Factors](#tRIFA)  | [6](#tRIFA) |
| [Special Note Regarding Forward-Looking Statements](#tSNRF)  | [7](#tSNRF) |
| [Use of Proceeds](#tUOP)  | [10](#tUOP) |
| [Selling Stockholders](#tSEST)  | [11](#tSEST) |
| [Description of Capital Stock](#tDOCS)  | [13](#tDOCS) |
| [Certain United States Federal Income Tax Consequences to Non-U.S. Holders](#tCUSF)  | [22](#tCUSF) |
| [Plan of Distribution](#tPOD)  | [25](#tPOD) |
| [Legal Matters](#tLEMA)  | [27](#tLEMA) |
| [Experts](#tEXP)  | [27](#tEXP) |
| [Where You Can Find More Information](#tWYCF)  | [28](#tWYCF) |
| [Information Incorporated by Reference](#tIIBR)  | [28](#tIIBR) |

---

 **You should rely only on the information contained or incorporated by reference in this prospectus supplement and the accompanying prospectus or any free writing prospectus we may authorize to be delivered or made available to you. Neither we nor the selling stockholders or the underwriter have authorized anyone to provide you with information or to make any representations different from those contained or incorporated by reference in this prospectus supplement and the accompanying prospectus or any free writing prospectus prepared by us or on our behalf. Neither we nor the selling stockholders or the underwriter take any responsibility for, or can provide any assurance as to the reliability of, any information other than the information contained or incorporated by reference in this prospectus supplement and the accompanying prospectus or any free writing prospectus prepared by us or on our behalf. This prospectus supplement and the accompanying prospectus or any applicable free writing prospectus is an offer to sell only the shares of common stock offered hereby, but only under circumstances where it is lawful to do so. The selling stockholders and the underwriter are not offering to sell shares of our common stock in any jurisdiction where an offer or sale is not permitted. The information contained in or incorporated by reference in this prospectus supplement and the accompanying prospectus or any free writing prospectus prepared by us or on our behalf is accurate only as of the date of this prospectus supplement, regardless of the time of delivery of this prospectus supplement and the accompanying prospectus or any applicable free writing prospectus prepared by us or on our behalf or any sale of shares of our common stock. Our business, results of operations, and financial condition may have changed since such date.** 

S-i

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For investors outside of the United States, neither we nor the selling stockholders or the underwriter have done anything that would permit this offering or the possession or distribution of this prospectus supplement and the accompanying prospectus or any applicable free writing prospectus in any jurisdiction where action for that purpose is required, other than in the United States. You are required to inform yourselves about and to observe any restrictions relating to the offering of shares of common stock and the possession or distribution of this prospectus supplement and the accompanying prospectus or any applicable free writing prospectus outside of the United States.

S-ii

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#### About This Prospectus Supplement
This document has two parts, a prospectus supplement and an accompanying prospectus dated July 14, 2025. This prospectus supplement and the accompanying prospectus are part of a registration statement that we filed with the SEC, utilizing the SEC's "shelf" registration process. The prospectus supplement, which describes certain matters relating to us and the specific terms of this offering of shares of our common stock, adds to and updates information contained in the accompanying prospectus and the documents incorporated by reference herein. Generally, when we refer to this document, we are referring to both parts of this document combined. Both this prospectus supplement and the accompanying prospectus include important information about us, our common stock, and other information you should know before investing in our common stock. To the extent the information contained in this prospectus supplement differs or varies from the information contained in the accompanying prospectus, you should rely on the information contained in this prospectus supplement. If the information contained in this prospectus supplement differs or varies from the information contained in a document we have incorporated by reference, you should rely on the information in the more recent document.

Before you invest in our common stock, you should read the registration statement of which this document forms a part and this document, including the documents incorporated by reference herein that are described under the heading "Incorporation by Reference."

The distribution of this prospectus supplement and the accompanying prospectus and the offering of the common stock in certain jurisdictions may be restricted by law. Neither the selling stockholders nor the underwriter are making an offer of the common stock in any jurisdiction where the offer is not permitted. Persons who come into possession of this prospectus supplement and the accompanying prospectus should inform themselves about and observe any such restrictions. This prospectus supplement and the accompanying prospectus do not constitute, and may not be used in connection with, an offer or solicitation by anyone in any jurisdiction in which such offer or solicitation is not authorized or in which the person making such offer or solicitation is not qualified to do so or to any person to whom it is unlawful to make such offer or solicitation.

You should not consider any information in this prospectus supplement or the accompanying prospectus to be investment, legal, or tax advice. You should consult your own counsel, accountant, and other advisors for legal, tax, business, financial, and related advice regarding the purchase of the common stock. None of us, the selling stockholders, or the underwriter are making any representation to you regarding the legality of an investment in the common stock by you under applicable investment or similar laws.

#### Industry and Market Data
This prospectus supplement incorporates by reference, and any accompanying prospectus or free writing prospectus may contain or incorporate by reference, market data and industry statistics and forecasts that are based on independent industry publications and other publicly available information. Although we believe these sources are reliable, neither we nor the selling stockholders or the underwriter can guarantee the accuracy or completeness of this information and we have not independently verified this information. In addition, the market and industry data and forecasts that may be included or incorporated by reference in this prospectus supplement, any accompanying prospectus, or any applicable free writing prospectus may involve estimates, assumptions, and other risks and uncertainties and are subject to change based on various factors, including those discussed under the heading "Risk Factors" in this prospectus supplement, and under similar headings in other documents that are incorporated by reference herein. Accordingly, investors should not place undue reliance on this information.

#### Trademarks, Service Marks, Tradenames, and Copyrights
We own a number of registered and common law trademarks and pending applications for trademark registrations in the United States. Unless otherwise indicated, all trademarks, service marks, trade names, and copyrights appearing in this prospectus supplement or incorporated by reference herein are proprietary to us, our affiliates, and/or licensors. This prospectus supplement and the documents incorporated by reference herein also contain trademarks, tradenames, service marks, and copyrights of third parties, which are the property of their respective owners. Solely for convenience, the trademarks, tradenames, service

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marks, and copyrights referred to in this prospectus supplement and in the information incorporated by reference herein may appear without the <sup>®</sup>, <sup>TM</sup>, <sup>SM</sup>, or <sup>©</sup> symbols, but such references are not intended to indicate, in any way, that we will not assert, to the fullest extent under applicable law, our rights or the rights of the applicable licensors to these trademarks, tradenames, service marks, and copyrights. We do not intend our use or display of other parties' trademarks, tradenames, service marks, or copyrights to imply, and such use or display should not be construed to imply, a relationship with, or endorsement or sponsorship of us by, these other parties.

#### Basis of Presentation
The following terms are used in this prospectus supplement and have the following meanings unless otherwise noted or indicated by the context:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • "Bain" means those certain investment funds of Bain Capital, LP and its affiliates;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • "CPPIB" means Canada Pension Plan Investment Board;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • "Credit Facilities" means, collectively, the First Lien Credit Facility, the Revolving Credit Facility, and the Receivables Facility;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • "DGCL" means the Delaware General Corporation Law, as amended;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • "EQT" means those certain investment funds of EQT AB and its affiliates;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • "Exchange Act" means the U.S. Securities Exchange Act of 1934, as amended;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • "First Lien Credit Facility" means the term loan credit facility under the first lien credit agreement, dated as of October 22, 2019, by and among Waystar Technologies, Inc. and the lenders party thereto, as amended from time to time;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • "Institutional Investors" means EQT, CPPIB, and Bain, and their respective affiliates;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • "Receivables Facility" means the receivables facility under the receivables financing agreement, dated as of August 13, 2021, by and among Waystar RC LLC, PNC Bank, National Association, as administrative agent, Waystar Technologies, Inc., as initial servicer, and PNC Capital Markets LLC, as structuring agent, as amended from time to time;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • "Revolving Credit Facility" means the revolving credit facility under the first lien credit agreement, dated as of October 22, 2019, by and among Waystar Technologies, Inc. and the lenders party thereto, as amended from time to time;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • "Sarbanes-Oxley Act" means the Sarbanes-Oxley Act of 2002, as amended;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • "SEC" means the U.S. Securities and Exchange Commission;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • "Securities Act" means the U.S. Securities Act of 1933, as amended;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • "selling stockholders" means Derby LuxCo S.à r.l., CPP Investment Board Private Holdings (4) Inc., BCPE Derby Investor, LP., and BCPE Derby (DE) SPV;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • "Stockholders Agreement" means the stockholders agreement, dated as of June 10, 2024, as amended as of April 10, 2025 and July 23, 2025, by and among the Institutional Investors, certain stockholders, and certain members of management;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • "underwriters" means the firms listed on the cover page of this prospectus supplement; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • "Waystar," the "Company," "we," "us," and "our" mean the business of Waystar Holding Corp. and its subsidiaries.

Numerical figures included in this prospectus supplement or in the documents incorporated by reference herein have been subject to rounding adjustments. Accordingly, numerical figures shown as totals in various tables may not be arithmetic aggregations of the figures that precede them.

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#### PROSPECTUS SUPPLEMENT SUMMARY
 *This summary highlights selected information contained or incorporated by reference in this prospectus supplement and the accompanying prospectus. This summary is not complete and does not contain all of the information that you should consider before making your investment decision. Before you decide to invest in shares of our common stock, you should carefully read this entire prospectus supplement, the accompanying prospectus, and the information incorporated by reference herein and therein, including any free writing prospectus prepared by us or on our behalf, including the sections entitled "Special Note Regarding Forward-Looking Statements" and "Risk Factors" included in this prospectus supplement and the accompanying prospectus, the sections entitled "Risk Factors" and "Management's Discussion and Analysis of Financial Condition and Results of Operations" and the audited consolidated financial statements and related notes thereto in [our Annual Report on Form 10-K for the fiscal year ended December 31, 2024](http://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000141057825000148/way-20241231x10k.htm), and the section entitled "Management's Discussion and Analysis of Financial Condition and Results of Operations" and the unaudited condensed consolidated financial statements and related notes thereto in our Quarterly Reports on Form 10-Q for the quarterly periods ended [March 31, 2025](http://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000141057825001048/way-20250331x10q.htm) and [June 30, 2025](http://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000199035425000012/way-20250630.htm), each of which is incorporated by reference in this prospectus supplement and the accompanying prospectus.* 

#### Our Mission
Our mission is to simplify healthcare payments through our modern cloud-based software, enabling our healthcare clients to prioritize patient care and optimize their financial performance.

#### Overview
Waystar provides healthcare organizations with mission-critical cloud software that simplifies healthcare payments. Our enterprise-grade platform streamlines the complex and disparate processes our healthcare provider clients must manage to be reimbursed correctly, while improving the payments experience for providers, patients, and payers. We leverage internally developed artificial intelligence ("AI") as well as proprietary, advanced algorithms to automate payment-related workflow tasks and drive continuous improvement, which enhances claim and billing accuracy, enriches data integrity, and reduces labor costs for providers.

Put simply, our software helps providers get paid faster, accurately, and more efficiently, while ensuring patients receive a modern, transparent, and consumer-friendly financial experience.

The healthcare payment ecosystem is highly complex, beginning with pre-service patient onboarding and extending through post-service revenue collection, with dozens of interdependent steps in between. Within this multi-step workflow, the process for determining how much a provider should be reimbursed involves millions of permutations of variables, such as over 10,000 diagnosis codes that are constantly changing and unique payer contracts, each with individual rules, processes, and reimbursement requirements. The burden borne by providers of tracking and managing all of these variables, coupled with a constantly evolving regulatory framework, often results in incorrect payments or denials that require time-consuming appeals procedures to resolve. Historically, healthcare providers have relied upon a patchwork of manual processes and systems to navigate these complexities and support their payment functions. However, this legacy approach has resulted in workflow delays, lost revenue, and slower time to payment. Our purpose-built software platform addresses these challenges and optimizes healthcare payments across all stages of the patient journey. Our clients utilize our software to manage pre-encounter workflows such as eligibility checks and prior authorization approvals, as well as mid- and post-encounter workflows such as co-pay collection, claims submission and monitoring, and payer remittances.

Our software is used daily by providers of all types and sizes across the continuum of care, including physician practices, clinics, surgical centers, and laboratories, as well as large hospitals and health systems. We currently serve over 30,000 clients of various sizes, representing over one million distinct providers practicing across a variety of care sites, including 16 of the top 20 U.S. News Best Hospitals. Our client base is highly diversified, and for the year ended December 31, 2024, our top 10 clients accounted for only 11.2% of our total revenue for such period. Our business model is designed such that as our clients grow to serve more patients, their claims and transactional volumes increase, resulting in corresponding growth in our business. In addition, our clients frequently adopt a greater number of our solutions over time and introduce

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our solutions across new sites of care. In 2024, we facilitated over six billion healthcare payments transactions, including over $1.8 trillion in gross claims volume. As of 2023, we facilitated healthcare payments transactions spanning approximately 50% of patients in the United States.

Our platform benefits from powerful network effects. Our cloud-based software is driven by a sophisticated, automated, and curated rules engine, employing AI to generate and incorporate real-time feedback from millions of network transactions processed through our platform each day. Every transaction we process provides additional data insights across providers, patients, and payers, which are embedded in updates that are deployed efficiently across our client base. This results in cumulative benefits to us over time as we capture more data from each transaction we process, we leverage that data to continue to improve the Waystar platform through embedded machine learning, advanced algorithms, and other in-house AI technologies to deliver added value to our clients. In turn, the more value we create for our clients, the more likely it is that they will continue to use our products, allowing us to continue to capture more data that results in tangible improvements to our platform. As a result, our clients benefit from faster and more efficient performance from software that is evolving to meet ever-changing regulatory and payer requirements, enabling accurate and timely reimbursement.

For a description of our business, financial condition, results of operations, and other important information regarding Waystar, we refer you to our filings with the SEC incorporated by reference in this prospectus supplement. For instructions on how to find copies of these documents, see "Where You Can Find More Information." We were originally incorporated in Delaware on August 13, 2019 and subsequently changed our name to Waystar Holding Corp. on August 11, 2023. Our principal offices are located at 1550 Digital Drive, #300, Lehi, Utah 84043 and 9901 Linn Station Road, Louisville, Kentucky 40223. Our telephone number is (844) 492-9782. We maintain a website at waystar.com. The reference to our website is intended to be an inactive textual reference only. The information contained on, or that can be accessed through, our website is not part of this prospectus supplement.

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#### The Offering
Common Stock Offered by the Selling Stockholders

18,000,000 shares.

Common Stock Outstanding

174,146,070 shares (as of June 30, 2025).

Use of Proceeds

The selling stockholders will receive all of the net proceeds from the sale of shares of common stock in this offering. We will not receive any proceeds from the sale of shares of common stock by the selling stockholders. For additional information, see "Use of Proceeds."

Institutional Investors

After this offering, EQT, CPPIB, and Bain will beneficially own approximately 14.3%, 10.9%, and 7.9%, respectively, of our common stock.

For so long as EQT, CPPIB, and Bain beneficially own 40% or more of the voting power of our total outstanding common stock, our stockholders will have certain corporate governance rights, such as the right to (i) fix the number of directors, (ii) at the request of at least two of EQT, CPPIB, and Bain, cause special meetings of our stockholders to be called, and (iii) amend our amended and restated certificate of incorporation and our amended and restated bylaws by majority vote rather than supermajority vote of our stockholders.

Further, each of EQT, CPPIB, and Bain currently has the right to nominate to our board of directors one nominee for so long as each such Institutional Investor beneficially owns 5% or greater of our then-outstanding common stock. In addition, the Institutional Investors have certain nomination rights with respect to our board committees. See "Description of Capital Stock — Anti-takeover Effects of Our Amended and Restated Certificate of Incorporation and Amended and Restated Bylaws, and Certain Provisions of Delaware Law — Director Nomination Rights" in the accompanying prospectus.

Dividend Policy

We have no current plans to pay dividends on our common stock. Any decision to declare and pay dividends in the future will be made at the sole discretion of our board of directors and will depend on, among other things, our results of operations, cash requirements, financial condition, legal, tax, regulatory, and contractual restrictions, including restrictions in the agreements governing our indebtedness, and other factors that our board of directors may deem relevant.

Risk Factors

Investing in shares of our common stock involves a high degree of risk. See "Risk Factors" for a discussion of factors you should carefully consider before investing in shares of our common stock.

Trading Symbol

"WAY"

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Except as otherwise indicated, all information in this prospectus supplement regarding the number of shares of our common stock that will be outstanding immediately after this offering is based on 174,146,070 shares of our common stock outstanding as of June 30, 2025, and:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • excludes 4,612,940 shares of our common stock underlying 4,612,940 restricted stock units that were outstanding as of June 30, 2025;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • excludes 14,981,933 shares of our common stock issuable upon exercise of outstanding stock options;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • does not reflect 5,489,286 shares of common stock available for future issuance under our 2024 Equity Incentive Plan and 3,250,000 shares of common stock available for future issuance under our 2024 Employee Stock Purchase Plan, in each case, as of June 30, 2025; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • excludes 16,751,541 shares of common stock to be issued in connection with the closing of the Company's acquisition of Iodine Software Holdings, Inc. ("Iodine").

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#### RISK FACTORS
 *Investing in our common stock involves a high degree of risk. You should carefully consider all of the risks and uncertainties described below and the other information set forth in this prospectus supplement and in our [Annual Report on Form 10-K for the fiscal year ended December 31, 2024](http://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000141057825000148/way-20241231x10k.htm) and in our Quarterly Reports on Form 10-Q for the quarterly periods ended [March 31, 2025](http://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000141057825001048/way-20250331x10q.htm) and [June 30, 2025](http://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000199035425000012/way-20250630.htm) before deciding to invest in shares of our common stock. If any of the following risks actually occurs, our business, results of operations, prospects, and financial condition may be materially adversely affected. In such case, the trading price of our common stock could decline, and you may lose all or part of your investment. Some statements in this prospectus supplement, including statements in the following risk factors, constitute forward-looking statements. See "Special Note Regarding Forward-Looking Statements."* 

#### Risks Related to this Offering and Ownership of Our Common Stock
 ***The Institutional Investors will continue to hold a significant percentage of our outstanding common stock after this offering and their interests may be different than the interests of other holders of our securities.***

Upon the completion of this offering, the Institutional Investors will own approximately 33.1% of our outstanding common stock. As a result, the Institutional Investors are able to control or influence actions to be taken by us, including future issuances of our common stock or other securities, the payment of dividends, if any, on our common stock, amendments to our organizational documents, and the approval of significant corporate transactions, including mergers, sales of substantially all of our assets, distributions of our assets, the incurrence of indebtedness, and any incurrence of liens on our assets.

The interests of the Institutional Investors may be materially different than the interests of our other stakeholders. In addition, the Institutional Investors may have an interest in pursuing acquisitions, divestitures, and other transactions that, in their judgment, could enhance their investment, even though such transactions might involve risks to you. For example, the Institutional Investors may cause us to take actions or pursue strategies that could impact our ability to make payments under our Credit Facilities or cause a change of control. In addition, to the extent permitted by agreements governing our Credit Facilities, the Institutional Investors may cause us to pay dividends rather than make capital expenditures or repay debt. The Institutional Investors are in the business of making investments in companies and may from time to time acquire and hold interests in businesses that compete directly or indirectly with us. Our amended and restated certificate of incorporation provides that none of the Institutional Investors, any of their respective affiliates, or any director who is not employed by us (including any non-employee director who serves as one of our officers in both his or her director and officer capacities) or his or her affiliates will have any duty to refrain from engaging, directly or indirectly, in the same business activities or similar business activities or lines of business in which we operate. The Institutional Investors also may pursue acquisition opportunities that may be complementary to our business, and, as a result, those acquisition opportunities may not be available to us.

So long as the Institutional Investors continue to own a significant amount of our outstanding common stock, even if such amount is less than 50%, they will continue to be able to strongly influence or effectively control our decisions and, so long as each of the Institutional Investors continues to own 5% or greater of our outstanding common stock, it will have the ability to nominate individuals to our board of directors. See "Description of Capital Stock" in the accompanying prospectus and the section entitled "Certain Relationships and Related Transactions and Director Independence-Stockholders Agreement" included in [our Annual Report on Form 10-K for the fiscal year ended December 31, 2024](http://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000141057825000148/way-20241231x10k.htm) and incorporated by reference herein. In addition, the Institutional Investors, acting together, will be able to significantly influence the outcome of all matters requiring stockholder approval, including a change of control of our company or a change in the composition of our board of directors and could preclude any unsolicited acquisition of our company. The concentration of ownership could deprive you of an opportunity to receive a premium for your shares of common stock as part of a sale of our company and ultimately might affect the market price of our common stock.

 ***Failure to comply with requirements to design, implement, and maintain effective internal controls could have a material adverse effect on our business and stock price.***

As a public company, we are subject to significant requirements for enhanced financial reporting and internal controls. The process of designing and implementing effective internal controls is a continuous

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effort that requires us to anticipate and react to changes in our business and the economic and regulatory environments and to expend significant resources to maintain a system of internal controls that is adequate to satisfy our reporting obligations as a public company. If we are unable to establish or maintain appropriate internal financial reporting controls and procedures, it could cause us to fail to meet our reporting obligations on a timely basis, result in material misstatements in our consolidated financial statements, and harm our results of operations. In addition, we are required, pursuant to Section 404(a) of the Sarbanes-Oxley Act ("Section 404"), to furnish a report by management on, among other things, the effectiveness of our internal control over financial reporting in the second annual report following the completion of our initial public offering. This assessment must include disclosure of any material weaknesses identified by our management in our internal control over financial reporting. The rules governing the standards that must be met for our management to assess our internal control over financial reporting are complex and require significant documentation, testing, and possible remediation. Testing and maintaining internal controls may divert our management's attention from other matters that are important to our business. Once we are no longer an "emerging growth company," our auditors will be required to issue an attestation report on the effectiveness of our internal controls on an annual basis.

In connection with the implementation of the necessary procedures and practices related to internal control over financial reporting, we may identify deficiencies that we may not be able to remediate in time to meet the deadline imposed by the Sarbanes-Oxley Act for compliance with the requirements of Section 404. In addition, we may encounter problems or delays in completing the remediation of any deficiencies identified by us or our independent registered public accounting firm in connection with the issuance of their attestation report. Our testing, or the subsequent testing (if required) by our independent registered public accounting firm, may reveal deficiencies in our internal controls over financial reporting that are deemed to be material weaknesses. Any material weaknesses could result in a material misstatement of our annual or quarterly financial statements or disclosures that may not be prevented or detected.

We may not be able to conclude on an ongoing basis that we have effective internal control over financial reporting in accordance with Section 404 or our independent registered public accounting firm may not issue an unqualified opinion. If either we are unable to conclude that we have effective internal control over financial reporting or our independent registered public accounting firm is unable to provide us with an unqualified report (to the extent it is required to issue a report), investors could lose confidence in our reported financial information, which could have a material adverse effect on the trading price of our common stock.

 ***The market price of our common stock has been volatile and may continue to fluctuate substantially, which could result in substantial losses for purchasers of our common stock.***

The stock market has experienced extreme volatility in the past. This volatility often has been unrelated or disproportionate to the operating performance of particular companies. Since shares of our common stock were sold in our initial public offering in June 2024 at a price of $21.50 per share, the market price of our common stock has fluctuated, and it may continue to fluctuate substantially due to a number of factors such as those listed in the section entitled "Risk Factors — Risks Related to our Business and our Industry" in [our Annual Report on Form 10-K for the fiscal year ended December 31, 2024](http://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000141057825000148/way-20241231x10k.htm) and incorporated by reference herein, in addition to the following:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • results of operations that vary from the expectations of securities analysts and investors;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • results of operations that vary from those of our competitors;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • changes in expectations as to our future financial performance, including financial estimates and investment recommendations by securities analysts and investors, or failure of securities analysts to initiate or maintain coverage of our common stock;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • changes in economic conditions for companies in our industry;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • changes in market valuations of, or earnings and other announcements by, companies in our industry;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • declines in the market prices of stocks generally, particularly those of healthcare technology companies or SaaS companies regardless of industry;

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • additions or departures of key management personnel;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • strategic actions by us or our competitors;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • announcements by us, our competitors, dispositions, joint ventures, other strategic relationships, or capital commitments;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • future sales of our common stock by our officers, directors, and significant stockholders;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • expiration of market standoff or lock-up agreements;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • changes in preference of our clients and our market share;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • changes in general economic or market conditions or trends in our industry or the economy as a whole;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • changes in business or regulatory conditions;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • future sales of our common stock or other securities;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • investor perceptions of or the investment opportunity associated with our common stock relative to other investment alternatives;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the public's response to press releases or other public announcements by us or third parties, including our filings with the SEC;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • changes or proposed changes in laws or regulations or differing interpretations or enforcement thereof affecting our business;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • announcements, claims and/or allegations relating to litigation, governmental investigations, or compliance with applicable laws and regulations;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • guidance, if any, that we provide to the public, any changes in this guidance, or our failure to meet this guidance;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the development and sustainability of an active trading market for our stock;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • changes in accounting principles; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • other events or factors, including those resulting from informational technology system failures and disruptions, data security incidents or breaches, natural disasters, war, including the ongoing conflict in Ukraine, acts of terrorism, or responses to these events.

Furthermore, the stock markets in general have experienced extreme volatility that, in some cases, may be unrelated or disproportionate to the operating performance of particular companies. These broad market and industry fluctuations may adversely affect the market price of our common stock, regardless of our actual operating performance. In addition, price volatility may be greater if the public float and trading volume of our common stock are low.

In the past, following periods of market volatility, stockholders have instituted securities class action litigation. If we were to become involved in securities litigation, it could have a substantial cost and divert resources and the attention of executive management from our business regardless of the outcome of such litigation.

 ***Because we have no current plans to pay cash dividends on our common stock, you may not receive any return on investment unless you sell your shares of common stock for a price greater than that which you paid for it.***

We have no current plans to pay cash dividends on our common stock. The declaration, amount, and payment of any future dividends will be at the sole discretion of our board of directors, and will depend on, among other things, general and economic conditions, our results of operations and financial condition, our available cash and current and anticipated cash needs, capital requirements, contractual, legal, tax, and regulatory restrictions and implications on the payment of dividends by us to our stockholders or by our subsidiaries to us, including restrictions under our credit agreements and other indebtedness we may incur, and such other factors as our board of directors may deem relevant.

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As a result, you may not receive any return on an investment in our common stock unless you sell our common stock for a price greater than your purchase price.

 ***Future sales, or the perception of future sales, by us or our existing stockholders in the public market following the completion of this offering could cause the market price for our common stock to decline.***

The sale of substantial amounts of shares of our common stock in the public market after this offering, or the perception that such sales could occur, could harm the prevailing market price of shares of our common stock. These sales, or the possibility that these sales may occur, also might make it more difficult for us to sell equity securities in the future at a time and at a price that we deem appropriate.

The selling stockholders and certain of our executive officers, and directors have signed lock-up agreements in connection with this offering that, subject to certain exceptions, restrict the sale of the shares of our common stock and certain other securities held by them for a period ending 60 days from the date of this prospectus supplement except with the prior written consent of the underwriter. Upon the expiration of such lock-up agreements, all of the outstanding 57,798,048 shares held by the selling stockholders, certain executive officers, and directors will be eligible for resale in a public market, subject to vesting in some cases and to volume, manner of sale, and other limitations under Rule 144 under the Securities Act.

In addition, pursuant to the Amended and Restated Registration Rights Agreement, dated as of June 10, 2024, by and among Waystar Holding Corp. and the other parties named therein, certain of our existing stockholders have the right, subject to certain conditions, to require us to register the sale of their shares of our common stock under the Securities Act. See "Certain Relationships and Related Transactions and Director Independence-Registration Rights Agreement" included in [our Annual Report on Form 10-K for the fiscal year ended December 31, 2024](http://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000141057825000148/way-20241231x10k.htm) and incorporated by reference herein. By exercising their demand registration rights and selling a large number of shares, such existing stockholders could cause the prevailing market price of our common stock to decline. Following completion of this offering, the shares covered by demand registration rights would represent approximately 33.1% of common stock outstanding. Registration of any of these outstanding shares of our common stock would result in such shares becoming freely tradable without compliance with Rule 144 under the Securities Act upon effectiveness of the registration statement.

We filed a registration statement on Form S-8 under the Securities Act to register common stock issued or reserved for issuance under our 2019 Stock Incentive Plan, 2024 Equity Incentive Plan, and 2024 Employee Stock Purchase Plan, which automatically became effective upon filing. Accordingly, shares registered under such registration statement are available for sale in the open market, unless such shares are subject to vesting restrictions or lock-up restrictions.

As restrictions on resale end, or if the existing stockholders exercise their registration rights, the market price of our shares of common stock could drop significantly if the holders of these restricted shares sell them or are perceived by the market as intending to sell them. These factors could also make it more difficult for us to raise additional funds through future offerings of our shares of common stock or other securities.

 ***If securities analysts do not publish research or reports about our business or if they downgrade our stock or our sector, our stock price and trading volume could decline.***

The trading market for our common stock depends in part on the research and reports that industry or financial analysts publish about us or our business. We do not control these analysts. Furthermore, if one or more of the analysts who do cover us downgrade our stock or our industry, or the stock of any of our competitors, or publish inaccurate or unfavorable research about our business, the price of our stock could decline. If one or more of these analysts ceases coverage of us or fails to publish reports on us regularly, we could lose visibility in the market, which in turn could cause our stock price or trading volume to decline.

#### Anti-takeover provisions in our organizational documents could delay or prevent a change of control.
Certain provisions of our amended and restated certificate of incorporation and amended and restated bylaws may have an anti-takeover effect and may delay, deter, or prevent a merger, acquisition, tender offer, takeover attempt, or other change of control transaction that a stockholder might consider in its best interest,

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including those attempts that might result in a premium over the market price for the shares held by our stockholders. These provisions provide for, among other things:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • a classified board of directors until the second annual meeting of stockholders after the date on which the Institutional Investors collectively own less than 15% in voting power of the then-outstanding power of the then-outstanding shares of stock of our Company entitled to vote generally in the election of directors, as a result of which our board of directors will be divided into three classes until such time, with each class serving for staggered three-year terms;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the ability of our board of directors to issue one or more series of preferred stock;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • advance notice requirements for nominations of directors by stockholders and for stockholders to include matters to be considered at our annual meetings;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • certain limitations on convening special stockholder meetings and taking stockholder action by written consent;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • during a protective period commencing on the day on which the Institutional Investors collectively beneficially own less than 40% in voting power of the then-outstanding shares of our common stock and ending at the second annual meeting of stockholders after the date on which the Institutional Investors collectively own less than 15% in voting power of the then-outstanding power of our common stock (such period, the "Protective Period"), the removal of directors only for cause and only upon the affirmative vote of the holders of at least 66 2∕3% of the shares of common stock entitled to vote generally in the election of directors; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • during the Protective Period, the required approval of at least 66 2∕3% of the voting power of the outstanding shares of capital stock entitled to vote generally in the election of directors, voting together as a single class, to adopt, amend, or repeal certain provisions of our amended and restated certificate of incorporation.

Further, EQT, CPPIB, and Bain each currently has the right to nominate to our board of directors one nominee for so long as each such Institutional Investor beneficially owns 5% or greater of our then-outstanding common stock.

These anti-takeover provisions could make it more difficult for a third party to acquire us, even if the third party's offer may be considered beneficial by many of our stockholders. These provisions also may have the effect of preventing changes in our board of directors and may make it more difficult to accomplish transactions that stockholders may otherwise deem to be in their best interests. As a result, our stockholders may be limited in their ability to obtain a premium for their shares.

#### Our board of directors is authorized to issue and designate shares of our preferred stock in additional series without stockholder approval.
Our amended and restated certificate of incorporation authorizes our board of directors, without the approval of our stockholders, to issue 100,000,000 shares of our preferred stock, subject to limitations prescribed by applicable law, rules and regulations and the provisions of our amended and restated certificate of incorporation, as shares of preferred stock in series, to establish from time to time the number of shares to be included in each such series and to fix the designation, powers, preferences, and rights of the shares of each such series, and the qualifications, limitations, or restrictions thereof. The powers, preferences, and rights of these additional series of preferred stock may be senior to or on parity with our common stock, which may reduce its value.

 ***Our amended and restated certificate of incorporation provides that the Court of Chancery of the State of Delaware (or if such court does not have jurisdiction, another state or the federal courts (as appropriate) located within the State of Delaware) will be the sole and exclusive forum for certain stockholder litigation matters, which could limit our stockholders' ability to obtain a favorable judicial forum for disputes with us or our directors, officers, employees, or stockholders.***

Our amended and restated certificate of incorporation provides that unless we consent to the selection of an alternative forum, the Court of Chancery of the State of Delaware (or if such court does not have

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Any person or entity purchasing or otherwise acquiring any interest in shares of our capital stock shall be deemed to have notice of and consented to the forum provisions in our amended and restated certificate of incorporation, except our stockholders will not be deemed to have waived (and cannot waive) compliance with the federal securities laws and the rules and regulations thereunder. This choice of forum provision may limit a stockholder's ability to bring a claim in a judicial forum that it finds favorable for disputes with us or any of our directors, officers, other employees, or stockholders which may discourage lawsuits with respect to such claims. Alternatively, if a court were to find the choice of forum provision contained in our amended and restated certificate of incorporation to be inapplicable or unenforceable in an action, we may incur additional costs associated with resolving such action in other jurisdictions, which could harm our business, results of operations, and financial condition.

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#### SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS
This prospectus supplement includes and incorporates by reference forward-looking statements, within the meaning of Section 27A of the Securities Act, Section 21E of the Exchange Act, and the Private Securities Litigation Reform Act of 1995, that reflect our current views with respect to, among other things, our operations and financial performance. Forward-looking statements include all statements that are not historical facts. These forward-looking statements are included throughout this prospectus supplement, including in the sections entitled "Prospectus Supplement Summary" and "Risk Factors" above, and in the sections entitled "Risk Factors," "Management's Discussion and Analysis of Financial Condition and Results of Operations," and "Business," each included in [our Annual Report on Form 10-K for the fiscal year ended December 31, 2024](http://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000141057825000148/way-20241231x10k.htm) and in the section entitled "Management's Discussion and Analysis of Financial Condition and Results of Operations" included in our Quarterly Reports on Form 10-Q for the quarterly periods ended [March 31, 2025](http://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000141057825001048/way-20250331x10q.htm) and [June 30, 2025](http://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000199035425000012/way-20250630.htm), each of which is incorporated by reference herein, and relate to matters such as our industry, business strategy, goals, and expectations concerning our market position, future operations, margins, profitability, capital expenditures, liquidity, and capital resources and other financial and operating information. We have used the words "anticipate," "assume," "believe," "continue," "could," "estimate," "expect," "intend," "may," "plan," "potential," "predict," "project," "future," "will," "seek," "foreseeable," the negative version of these words, or similar terms and phrases to identify forward-looking statements in this prospectus supplement.

The forward-looking statements contained in or incorporated by reference into this prospectus supplement are based on management's current expectations and are not guarantees of future performance. The forward-looking statements are subject to various risks, uncertainties, assumptions, or changes in circumstances that are difficult to predict or quantify. Our expectations, beliefs, and projections are expressed in good faith and we believe there is a reasonable basis for them. However, there can be no assurance that management's expectations, beliefs, and projections will result or be achieved. Actual results may differ materially from these expectations due to changes in global, regional, or local economic, business, competitive, market, regulatory, and other factors, many of which are beyond our control. We believe that these factors include but are not limited to those described under "Risk Factors" above and in our [Annual Report on Form 10-K for the fiscal year ended December 31, 2024](http://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000141057825000148/way-20241231x10k.htm) and our Quarterly Reports on Form 10-Q for the quarterly periods ended [March 31, 2025](http://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000141057825001048/way-20250331x10q.htm) and [June 30, 2025](http://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000199035425000012/way-20250630.htm) incorporated by reference herein, and include the following:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our operation in a highly competitive industry;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our ability to retain our existing clients and attract new clients;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our ability to successfully execute on our business strategies in order to grow;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our ability to accurately assess the risks related to acquisitions and successfully integrate acquired businesses, including the previously announced acquisition of Iodine;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our ability to establish and maintain strategic relationships;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the growth and success of our clients and overall healthcare transaction volumes;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • consolidation in the healthcare industry;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our selling cycle of variable length to secure new client agreements;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our implementation cycle that is dependent on our clients' timing and resources;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our dependence on our senior management team and certain key employees, and our ability to attract and retain highly skilled employees;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the accuracy of the estimates and assumptions we use to determine the size of our total addressable market;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our ability to develop and market new solutions, or enhance our existing solutions, to respond to technological changes or evolving industry standards;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the interoperability, connectivity, and integration of our solutions with our clients' and their vendors' networks and infrastructures;

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the performance and reliability of internet, mobile, and other infrastructure;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the consequences if we cannot obtain, process, use, disclose, or distribute the highly regulated data we require to provide our solutions;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our reliance on certain third-party vendors and providers;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • any errors or malfunctions in our products and solutions;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • failure by our clients to obtain proper permissions or provide us with accurate and appropriate information;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the potential for embezzlement, identity theft, or other similar illegal behavior by our employees or vendors and a failure of our employees or vendors to observe quality standards or adhere to environmental, social, and governance standards;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our compliance with the applicable rules of the National Automated Clearing House Association and the applicable requirements of card networks;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • increases in card network fees and other changes to fee arrangements;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the effect of payer and provider conduct which we cannot control;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • privacy concerns and security breaches or incidents relating to our platform;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the complex and evolving laws and regulations regarding privacy, data protection, and cybersecurity;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our ability to adequately protect and enforce our intellectual property rights;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our ability to use or license data and integrate third-party technologies;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our use of "open source" software;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • legal proceedings initiated by third parties alleging that we are infringing or otherwise violating their intellectual property rights;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • claims that our employees, consultants, or independent contractors have wrongfully used or disclosed confidential information of third parties;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the heavily regulated industry in which we conduct business;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the uncertain and evolving healthcare regulatory and political framework;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • health care laws and data privacy and security laws and regulations governing our processing of personal information;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • reduced revenues in response to changes to the healthcare regulatory landscape;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • legal, regulatory, and other proceedings that could result in adverse outcomes;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • consumer protection laws and regulations;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • contractual obligations requiring compliance with certain provisions of the Bank Secrecy Act / anti-money laundering laws and regulations;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • existing laws that regulate our ability to engage in certain marketing activities;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our full compliance with website accessibility standards;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • any changes in our tax rates, the adoption of new tax legislation, or exposure to additional tax liabilities;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • limitations on our ability to use our net operating losses to offset future taxable income;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • losses due to asset impairment charges;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • restrictive covenants in the agreements governing our Credit Facilities;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • interest rate fluctuations;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • unavailability of additional capital on acceptable terms or at all;

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the impact of general macroeconomic conditions;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our history of net losses and our ability to achieve or maintain profitability;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the interests of the Institutional Investors may be different than the interests of other holders of our securities;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our status as an "emerging growth company" and whether the reduced disclosure requirements applicable to "emerging growth companies" will make our common stock less attractive to investors; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the other factors disclosed or incorporated by reference in this prospectus supplement.

These factors should not be construed as exhaustive and should be read in conjunction with the other cautionary statements that are included in or incorporated by reference into this prospectus supplement. Should one or more of these risks or uncertainties materialize, or should any of our assumptions prove incorrect, our actual results may vary in material respects from those projected in these forward-looking statements.

Any forward-looking statements made by us in or incorporated by reference into this prospectus supplement speak only as of the date of this prospectus supplement or the document incorporated or deemed incorporated by reference herein and are expressly qualified in their entirety by the cautionary statements included in or incorporated by reference into this prospectus supplement. Factors or events that could cause our actual results to differ may emerge from time to time, and it is not possible for us to predict all of them. You should not place undue reliance on our forward-looking statements. We undertake no obligation to publicly update or review any forward-looking statement, whether as a result of new information, future developments, or otherwise, except as may be required by any applicable securities laws.

Investors and others should note that we routinely announce financial and other material information using our Investor Relations website (investors.waystar.com), SEC filings, press releases, public conference calls, and webcasts. We use these channels of distribution to communicate with our investors and members of the public about our company, our services, and other items of interest. Information contained on our website is not part of this prospectus supplement or our other filings with the SEC.

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#### USE OF PROCEEDS
The selling stockholders will receive all of the net proceeds from the sale of shares of common stock in this offering. We are not selling any shares of common stock under this prospectus supplement and will not receive any proceeds from the sale of shares by the selling stockholders. The selling stockholders will bear the underwriting discount attributable to their sale of our common stock, and expenses incurred by the selling stockholders for brokerage, accounting, tax services, or any other expenses incurred by the selling stockholders, except we will bear the fees and expenses of up to two counsels for the selling stockholders. We will bear all other costs, fees, and expenses incurred in effecting the registration of the shares covered by this prospectus supplement, including, without limitation, all registration and filing fees, and fees and expenses of our counsel and our independent registered public accountants. See "Selling Stockholders."

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#### SELLING STOCKHOLDERS
The following table contains information about the beneficial ownership of our common stock as of July 21, 2025, (i) immediately prior to the consummation of this offering and (ii) as adjusted to reflect the sale of shares of our common stock offered by this prospectus supplement by all selling stockholders.

Our calculation of the percentage of beneficial ownership prior to and after the offering is based on 174,238,972 shares of our common stock outstanding as of July 21, 2025.

Beneficial ownership and percentage ownership are determined in accordance with the rules and regulations of the SEC. Under SEC rules, a person is deemed to be a "beneficial owner" of a security if that person has or shares voting power or investment power, which includes the power to dispose of or to direct the disposition of such security. A person is also deemed to be a beneficial owner of any securities of which that person has a right to acquire beneficial ownership within 60 days. Securities that can be so acquired are deemed to be outstanding for purposes of computing such person's ownership percentage, but not for purposes of computing any other person's percentage. Under these rules, more than one person may be deemed to be a beneficial owner of the same securities and a person may be deemed to be a beneficial owner of securities as to which such person has no economic interest. Except as indicated in the footnotes to the following table or pursuant to applicable community property laws, we believe, based on information furnished to us, that each stockholder named in the table has sole voting and investment power with respect to the shares set forth opposite such stockholder's name.

To our knowledge, unless otherwise noted in the footnotes to the table below, and subject to applicable community property laws, the persons named in the table have sole voting and investment power with respect to their beneficially owned common stock.

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| | | | | | |
|:---|:---|:---|:---|:---|:---|
| | **Shares Beneficially Owned Prior <br> to the Offering**  | **Shares Beneficially Owned Prior <br> to the Offering**  | **Shares to be <br> Sold in this <br> Offering**  | **Shares Beneficially Owned After <br> the Offering**  | **Shares Beneficially Owned After <br> the Offering**  |
| **Name of Beneficial Owner**  | **Number**  | **Percentage of <br> Total Common <br> Stock**  | **Number**  | **Number**  | **Percentage of <br> Total Common <br> Stock**  |
| EQT<sup>(1)</sup> | 32645525 | 18.7% | 7766088 | 24879437 | 14.3% |
| CPPIB<sup>(2)</sup> | 24964225 | 14.3% | 5938773 | 19025452 | 10.9% |
| Bain<sup>(3)</sup> | 18055049 | 10.4% | 4295139 | 13759910 | 7.9% |

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(1) Consists of shares of common stock held directly by Derby LuxCo S.à r.l. ("Derby LuxCo"). Several investment vehicles collectively make up the fund known as "EQT VIII." EQT VIII owns 100% of the membership interests in Derby LuxCo. EQT Fund Management S.à r.l. ("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 that acts by majority approval. The individual members of such board are Sara Huda, Magnus Sjöcrona, Leif Patrik Burnäs, Peter Veldman, and Christiaan Snyders. The registered address of EFMS and Derby LuxCo is 51A, Boulevard Royal, L-2449 Luxembourg, Grand Duchy of Luxembourg.

(2) CPPIB, through its wholly-owned subsidiary CPP Investment Board Private Holdings (4) Inc., beneficially owns 24,964,225 shares of common stock. Investment and voting power with regard to shares held by CPP Investment Board Private Holdings (4) Inc. rests with CPPIB. John Graham is the President and Chief Executive Officer of CPPIB and, in such capacity, may be deemed to have voting and dispositive power with respect to the shares of common stock beneficially owned by CPPIB. Mr. Graham disclaims beneficial ownership over any such shares. The address of CPPIB is One Queen Street East, Suite 2500, Toronto, Ontario, M5C 2W5, Canada.

(3) Consists of 2,609,155 shares of common stock held directly by BCPE Derby Investor, LP ("BCPE Derby") and 15,445,894 shares of common stock held directly by BCPE Derby (DE) SPV, LP ("BCPE Derby SPV"). Bain Capital Investors, LLC ("BCI") is the manager of Bain Capital Partners XI, LP, which is the general partner of Bain Capital Fund XI, LP ("Fund XI"). Fund XI is the (i) sole member of BCPE Derby GP, LLC, which is the general partner of BCPE Derby and (ii) sole member of BCPE Derby (DE) SPV, LLC, which is the general partner of BCPE Derby SPV. As a result, BCI may

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be deemed to share voting and dispositive power with respect to the shares held by BCPE Derby and BCPE Derby SPV. Voting and investment decisions with respect to securities held BCPE Derby and BCPE Derby SPV are made by the partners of BCI, of whom there are three or more and none of whom individually has the power to direct such decisions. The address of BCPE Derby and BCPE Derby SPV is c/o Bain Capital Private Equity, LP, 200 Clarendon Street, Boston, MA 02116.

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#### UNDERWRITING
J.P. Morgan Securities LLC is acting as the underwriter for this offering. Subject to the terms and conditions set forth in an underwriting agreement among us, the selling stockholders and the underwriter, the selling stockholders have agreed to sell to the underwriter, and the underwriter has agreed to purchase from the selling stockholders, the number of shares of common stock set forth opposite its name below.

---

| | |
|:---|:---|
| **Underwriter**  | **Number of Shares**  |
| J.P. Morgan Securities LLC  | 18000000 |
| Total  | 18000000 |

---

The underwriter is committed to purchase all the shares of common stock offered by the selling stockholders if they purchase any shares.

#### Discounts and Concessions
Shares sold by the underwriter to the public will initially be offered at the public offering price set forth on the cover page of this prospectus supplement. Any shares sold by the underwriter to securities dealers may be sold at a discount of up to $0.19 per share from the public offering price. After the initial offering, the public offering price, concession, or any other term of the offering may be changed. The offering of the shares by the underwriter is subject to receipt and acceptance and subject to the underwriter's right to reject any order in whole or in part. Sales of any shares made outside of the United States may be made by affiliates of the underwriter.

The following table shows the per share and total public offering price, underwriting discount, and proceeds before expenses to the selling stockholders.

---

| | | |
|:---|:---|:---|
| | **Per Share**  | **Total**  |
| Public offering price  | $39.40 | $709200000 |
| Underwriting discount  | $0.19 | $3420000 |
| Proceeds, before expenses, to the selling stockholders  | $39.21 | $705780000 |

---

We estimate that the total expenses of this offering, including registration, filing and listing fees, printing fees, and legal and accounting expenses, but excluding the underwriting discount, will be approximately $0.7 million. We have also agreed to reimburse the underwriter for certain of its expenses in an amount up to $35,000.

We have agreed that we will not (i) offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right, or warrant to purchase, lend, or otherwise transfer or dispose of, directly or indirectly, or submit to, or file with, the SEC a registration statement under the Securities Act relating to, any shares of our common stock or securities convertible into or exercisable or exchangeable for any shares of our common stock, or publicly disclose the intention to undertake any of the foregoing, or (ii) enter into any swap or other agreement that transfers all or a portion of the economic consequences associated with the ownership of any shares of common stock or any such other securities (regardless of whether any of these transactions are to be settled by the delivery of shares of common stock or such other securities, in cash or otherwise), in each case, without the prior written consent of the underwriter for a period beginning on the date of this prospectus supplement and ending at 12:01 am, New York time, on the 60th day after the date of this prospectus supplement, other than the shares of our common stock to be sold in this offering, subject to certain exceptions.

The restrictions on our actions, as described above, do not apply to certain transactions, including (i) any grants of options or other equity awards or issuances of shares of our common stock upon the exercise of options or other equity awards, in each case, granted under the terms of an equity compensation plan as described in the accompanying prospectus to this prospectus supplement, (ii) any filing by us of a registration statement on Form S-8 relating to any equity compensation plan or arrangement described in the accompanying prospectus to this prospectus supplement or any assumed benefit plan pursuant to an acquisition or similar strategic transaction, (iii) any shares of our common stock issued upon the exercise,

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conversion, or exchange of our securities outstanding as of the date of this prospectus supplement and described in the accompanying prospectus to this prospectus supplement, (iv) up to 5.0% of the total number of outstanding shares of our common stock issued by us in connection with mergers, acquisitions, or commercial or strategic transactions (including, without limitation, entry into joint ventures, marketing, or distribution agreements or collaboration agreements or acquisitions of technology, assets, or intellectual property licenses), and (v) confidential submission with the SEC or the Financial Industry Regulatory Authority, Inc. of any registration statement under the Securities Act; provided that in the case of clauses (i) through (iii), we shall cause each recipient that is a member of our board of directors, one of our executive officers, or a beneficial holder of 5.0% or more of our fully diluted capital stock to execute a lock-up agreement for the restricted period subject to the terms and conditions summarized herein, if not already a party thereto; provided, further, that in the case of clause (iv), we shall cause each recipient to execute a lock-up agreement for the restricted period.

Certain of our directors and executive officers and the selling stockholders (such persons, the "lock-up parties") have entered into lock-up agreements with the underwriter prior to the commencement of this offering pursuant to which each lock-up party, with limited exceptions, for a period beginning on the date of this prospectus supplement and ending at 12:01 am, New York time, on the 60th day after the date of this prospectus supplement, may not (and may not cause any of their direct or indirect affiliates to), without the prior written consent of the underwriter, (1) offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right, or warrant to purchase, lend or otherwise transfer or dispose of, directly or indirectly, any shares of our common stock or any securities convertible into or exercisable or exchangeable for our common stock (including, without limitation, common stock or such other securities which may be deemed to be beneficially owned by such lock-up parties in accordance with the rules and regulations of the SEC and securities which may be issued upon exercise of a stock option or warrant (collectively with the common stock, the "lock-up securities")), (2) enter into any hedging, swap, or other agreement or transaction that transfers, in whole or in part, any of the economic consequences of ownership of the lock-up securities, whether any such transaction described in clause (1) or (2) above is to be settled by delivery of lock-up securities, in cash or otherwise, (3) make any demand for, or exercise any right with respect to, the registration of any lock-up securities, or (4) publicly disclose the intention to do any of the foregoing. Such persons or entities have further acknowledged that these undertakings preclude them from engaging in any hedging or other transactions or arrangements (including, without limitation, any short sale or the purchase or sale of, or entry into, any put or call option, or combination thereof, forward, swap or any other derivative transaction or instrument, however described or defined) designed, or intended, or which could reasonably be expected, to lead to or result in a sale, disposition or transfer (by any person or entity, whether or not a signatory to such agreement) of any economic consequences of ownership, in whole or in part, directly or indirectly, of any lock-up securities, whether any such transaction or arrangement (or instrument provided for thereunder) would be settled by delivery of lock-up securities, in cash or otherwise.

The restrictions described in the immediately preceding paragraph and contained in the lock-up agreements between the underwriter and the lock-up parties do not apply, subject in certain cases to various conditions, to certain transactions, including: (a) transfers of lock-up securities: (i) as bona fide gifts, or for bona fide estate planning purposes; (ii) by will or intestacy; (iii) to any trust for the direct or indirect benefit of the lock-up party or any immediate family member; (iv) to any immediate family member of the lock-up party; (v) to a nominee or custodian of a person or entity to whom a disposition or transfer would be permissible under clauses (i) through (iv); (vi) by operation of law; (vii) to us from a current or former employee of ours upon death, disability, or termination of employment of such employee or to us pursuant to any contractual arrangement that provides us with a right to purchase lock-up securities; (viii) if the lock-up party is not a natural person, to any (1) corporation, partnership, limited liability company, trust or other entity, in each case, that controls, or is controlled by or is under common control with, the lock-up party or its immediate family, or is otherwise a direct or indirect affiliate (as defined in Rule 405 promulgated under the Securities Act) of the lock-up party, or (2) investment fund or other entity controlling, controlled by, managing or managed by or under common control with the lock-up party or its affiliates or as part of a distribution, transfer or disposition by the lock-up party to its stockholders, partners, members or other equity holders; (ix) as part of a sale of lock-up securities acquired in open-market transactions after the completion of this offering; (x) to us in connection with the vesting, settlement or exercise of restricted stock units, options, warrants or other rights to purchase shares of our common stock (including "net" or

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"cashless" exercise), including for the payment of exercise price and tax and remittance payments; (xi) pursuant to a bona fide third-party tender offer, merger, consolidation or other similar transaction approved by our board of directors and made to all stockholders involving a change in control in which the acquiring party or "group" (within the meaning of Section 13(d)(3) of the Exchange Act) of persons becomes the beneficial owner of more than 50% of the total voting power of the voting stock of us following such transaction; *provided* that if such transaction is not completed, all such lock-up securities would remain subject to the restrictions in the immediately preceding paragraph; (xii) in connection with any reclassification or conversion of our common stock; (xiii) to the lock-up party's direct or indirect general partner or managing member or to certain officers, partners, or members thereof in connection with such general partner's, managing member's, officers', partners' or members' donation to charitable organizations, educational institutions, family foundations or donor advised funds at sponsoring organizations; (xiv) in connection with the sales of shares of common stock pursuant to a trading plan under Rule 10b5-1 of the Exchange Act; (xv) the sale of shares of common stock to the underwriter pursuant to the underwriting agreement; or (xvi) for Institutional Investors only, pursuant to the pledge, hypothecation or other granting of a security interest in lock-up securities to one or more lending institutions as collateral or security for any loan, advance or extension of credit and any transfer upon foreclosure upon such securities; *provided*, that (unless entered into prior to the execution of the lock-up agreement) prior to entering into the collateral agreement or similar agreement in connection with the loan, advance or extension of credit, each pledgee shall enter into a lock-up agreement to take effect in the event that the pledgee takes possession of such lock-up party's lock-up securities as a result of a foreclosure, margin call or similar disposition; *provided further*, that the lock-up party shall provide the underwriter with prior written notice informing it of any public filing, report or announcement with respect to such pledge, hypothecation or other grant of a security interest or foreclosure; *provided further* that for any pledge, hypothecation, granting of security entered into after the execution of the lock-up agreement, the aggregate amount of lock-up securities pledged as collateral pursuant to this clause (together with any shares pledged prior to the execution of the lock-up agreement) during the restricted period shall not exceed 10% of the total number of shares of common stock beneficially owned by the applicable lock-up party; (b) exercise of the options, settlement of restricted stock units or other equity awards, or the exercise of warrants, granted pursuant to plans described in this prospectus supplement; *provided* that any lock-up securities received upon such exercise, vesting or settlement would be subject to restrictions similar to those in the immediately preceding paragraph; and (c) the establishment by lock-up parties of trading plans under Rule 10b5-1 under the Exchange Act; *provided* that such plan does not provide for the transfer of lock-up securities during the restricted period.

The underwriter, in its sole discretion, may release the common stock and other securities subject to the lock-up agreements described above in whole or in part at any time.

We have agreed to indemnify the underwriter against certain liabilities, including liabilities under the Securities Act.

Our common stock is listed on Nasdaq under the symbol "WAY."

The underwriter has advised us that, pursuant to Regulation M of the Securities Act, it may also engage in other activities that stabilize, maintain, or otherwise affect the price of the common stock, including the imposition of penalty bids. This means that if the representatives of the underwriter purchase common stock in the open market in stabilizing transactions or to cover short sales, the representatives can require the underwriter that sold those shares as part of this offering to repay the underwriting discount received by them.

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These activities may have the effect of raising or maintaining the market price of the common stock or preventing or retarding a decline in the market price of the common stock, and, as a result, the price of the common stock may be higher than the price that otherwise might exist in the open market. If the underwriter commences these activities, it may discontinue them at any time. The underwriter may carry out these transactions on Nasdaq, in the over-the-counter market, or otherwise.

Other than in the United States, no action has been taken by us or the underwriter that would permit a public offering of the securities offered by this prospectus supplement in any jurisdiction where action for that purpose is required. The securities offered by this prospectus supplement may not be offered or sold, directly or indirectly, nor may this prospectus supplement or any other offering material or advertisements in connection with the offer and sale of any such securities be distributed or published in any jurisdiction, except under circumstances that will result in compliance with the applicable rules and regulations of that jurisdiction. Persons into whose possession this prospectus supplement comes are advised to inform themselves about and to observe any restrictions relating to the offering and the distribution of this prospectus supplement. This prospectus supplement does not constitute an offer to sell or a solicitation of an offer to buy any securities offered by this prospectus supplement in any jurisdiction in which such an offer or a solicitation is unlawful.

The underwriter and its affiliates have provided in the past to us and our affiliates and may provide from time to time in the future certain commercial banking, financial advisory, investment banking, and other services for us and such affiliates in the ordinary course of their business, for which they have received and may continue to receive customary fees and commissions. In addition, from time to time, the underwriter and its affiliates may effect transactions for their own account or the account of customers, and hold on behalf of themselves or their customers, long or short positions in our debt or equity securities or loans, and may do so in the future. The underwriter and/or certain of its affiliates are lenders and/or agents under the Credit Facilities, and accordingly, are entitled to fees and expenses in connection therewith.

#### Selling restrictions outside the United States

#### Notice to prospective investors in the European Economic Area and the United Kingdom
In relation to each Member State of the European Economic Area and the United Kingdom (each a "Relevant State"), no shares of common stock have been offered or will be offered pursuant to this offering to the public in that Relevant State prior to the publication of a prospectus in relation to the shares which has been approved by the competent authority in that Relevant State or, where appropriate, approved in another Relevant State and notified to the competent authority in that Relevant State, all in accordance with the Prospectus Regulation and the UK Prospectus Regulation (each as defined below), except that offers of shares may be made to the public in that Relevant State at any time under the following exemptions under the Prospectus Regulation and the UK Prospectus Regulation:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; (a)

to any legal entity which is a qualified investor as defined under the Prospectus Regulation and/or Article 2 of the UK Prospectus Regulation, as applicable;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; (b)

to fewer than 150 natural or legal persons (other than qualified investors as defined under the Prospectus Regulation and/or Article 2 of the UK Prospectus Regulation, as applicable), subject to obtaining the prior consent of the underwriter; or

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; (c)

in any other circumstances falling within Article 1(4) of the Prospectus Regulation or Section 86 of the Financial Services and Markets Act 2000 ("FSMA");

*provided* that no such offer of shares shall require us or any underwriter to publish a prospectus pursuant to Article 3 of the Prospectus Regulation or Section 85 of the FSMA or supplement a prospectus pursuant to Article 23 of the Prospectus Regulation or Article 23 of the UK Prospectus Regulation, and each person who initially acquires any shares or to whom any offer is made will be deemed to have represented, acknowledged and agreed to and with the underwriter and us that it is a "qualified investor" within the meaning of Article 2(e) of the Prospectus Regulation and/or Article 2(e) of the UK Prospectus Regulation, as applicable. In the case of any shares being offered to a financial intermediary as that term is used in the Prospectus Regulation and/or Article 5(1) of the UK Prospectus Regulation, as applicable, each such financial

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intermediary will be deemed to have represented, acknowledged and agreed that the shares acquired by it in the offer have not been acquired on a non-discretionary basis on behalf of, nor have they been acquired with a view to their offer or resale to, persons in circumstances which may give rise to an offer of any shares to the public other than their offer or resale in a Relevant State to qualified investors as so defined or in circumstances in which the prior consent of the underwriter has been obtained to each such proposed offer or resale.

For the purposes of this provision and the following provision, the expression "offer to the public" in relation to shares in any Relevant State means the communication in any form and by any means of sufficient information on the terms of the offer and any shares to be offered so as to enable an investor to decide to purchase or subscribe for any shares, the expression "Prospectus Regulation" means Regulation (EU) 2017/1129, and the expression "UK Prospectus Regulation" means assimilated Regulation (EU) 2017/1129 as it forms part of the domestic law of the United Kingdom by virtue of the European Union (Withdrawal) Act 2018.

#### Notice to prospective investors in the United Kingdom
In addition, in the United Kingdom, this document is being distributed only to, and is directed only at, and any offer subsequently made may only be directed at persons who are, "qualified investors" (as defined in Article 2(e) of the UK Prospectus Regulation) (i) who have professional experience in matters relating to investments falling within Article 19(5) of the Financial Services and Markets Act 2000 (Financial Promotion) Order 2005, as amended (the "Order"), and/or (ii) who are high net worth companies (or persons to whom it may otherwise be lawfully communicated) falling within Article 49(2)(a) to (d) of the Order (all such persons together being referred to as "relevant persons") or otherwise in circumstances which have not resulted and will not result in an offer to the public of the shares in the United Kingdom within the meaning of the Financial Services and Markets Act 2000.

Any person in the United Kingdom that is not a relevant person should not act or rely on the information included in this document or use it as basis for taking any action. In the United Kingdom, any investment or investment activity that this document relates to may be made or taken exclusively by relevant persons.

#### Notice to prospective investors in Canada
The shares may be sold only to purchasers purchasing, or deemed to be purchasing, as principal that are accredited investors, as defined in National Instrument 45-106 Prospectus Exemptions or subsection 73.3(1) of the Securities Act (Ontario), and are permitted clients, as defined in National Instrument 31-103 Registration Requirements, Exemptions and Ongoing Registrant Obligations. Any resale of the shares must be made in accordance with an exemption from, or in a transaction not subject to, the prospectus requirements of applicable securities laws.

Securities legislation in certain provinces or territories of Canada may provide a purchaser with remedies for rescission or damages if this prospectus supplement (including any amendment thereto) contains a misrepresentation; *provided* that the remedies for rescission or damages are exercised by the purchaser within the time limit prescribed by the securities legislation of the purchaser's province or territory. The purchaser should refer to any applicable provisions of the securities legislation of the purchaser's province or territory for particulars of these rights or consult with a legal advisor.

Pursuant to section 3A.3 of National Instrument 33-105 Underwriting Conflicts (NI 33-105), the underwriter is not required to comply with the disclosure requirements of NI 33-105 regarding underwriter conflicts of interest in connection with this offering.

#### Notice to prospective investors in Switzerland
The shares may not be publicly offered in Switzerland and will not be listed on the SIX Swiss Exchange (the "SIX") or on any other stock exchange or regulated trading facility in Switzerland. This document does not constitute a prospectus within the meaning of, and has been prepared without regard to the disclosure standards for issuance prospectuses under, art. 652a or art. 1156 of the Swiss Code of Obligations or the disclosure standards for listing prospectuses under art. 27 ff. of the SIX Listing Rules or the listing rules

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of any other stock exchange or regulated trading facility in Switzerland. Neither this document nor any other offering or marketing material relating to the shares or this offering may be publicly distributed or otherwise made publicly available in Switzerland. Neither this document nor any other offering or marketing material relating to this offering, us or the shares has been or will be filed with or approved by any Swiss regulatory authority. In particular, this document will not be filed with, and the offer of shares will not be supervised by, the Swiss Financial Market Supervisory Authority, and the offer of shares has not been and will not be authorized under the Swiss Federal Act on Collective Investment Schemes (the "CISA"). The investor protection afforded to acquirers of interests in collective investment schemes under the CISA does not extend to acquirers of shares.

#### Notice to prospective investors in the Dubai International Financial Centre (the "DIFC")
This document relates to an "Exempt Offer" in accordance with the Markets Rules 2012 of the Dubai Financial Services Authority (the "DFSA"). This document is intended for distribution only to persons of a type specified in the Markets Rules 2012 of the DFSA. It must not be delivered to, or relied on by, any other person. The DFSA has no responsibility for reviewing or verifying any documents in connection with Exempt Offers. The DFSA has not approved this prospectus supplement or taken steps to verify the information set forth herein and has no responsibility for this document. The securities to which this document relates may be illiquid and/or subject to restrictions on their resale. Prospective purchasers of the securities offered should conduct their own due diligence on the securities. If you do not understand the contents of this document you should consult an authorized financial advisor.

In relation to its use in the DIFC, this document is strictly private and confidential and is being distributed to a limited number of investors and must not be provided to any person other than the original recipient, and may not be reproduced or used for any other purpose. The interests in the securities may not be offered or sold directly or indirectly to the public in the DIFC.

#### Notice to prospective investors in Australia
This prospectus supplement:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • does not constitute a disclosure document or a prospectus under Chapter 6D.2 of the Corporations Act 2001 (Cth) (the "Corporations Act");

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • has not been, and will not be, lodged with the Australian Securities and Investments Commission (the "ASIC") as a disclosure document for the purposes of the Corporations Act and does not purport to include the information required of a disclosure document for the purposes of the Corporations Act; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • may only be provided in Australia to select investors who are able to demonstrate that they fall within one or more of the categories of investors available under section 708 of the Corporations Act ("Exempt Investors").

The shares may not be directly or indirectly offered for subscription or purchased or sold, and no invitations to subscribe for or buy the shares may be issued, and no draft or definitive offering memorandum, advertisement or other offering material relating to any shares may be distributed, in Australia, except where disclosure to investors is not required under Chapter 6D of the Corporations Act or is otherwise in compliance with all applicable Australian laws and regulations. By submitting an application for the shares, you represent and warrant to us that you are an Exempt Investor.

As any offer of shares under this document will be made without disclosure in Australia under Chapter 6D.2 of the Corporations Act, the offer of those securities for resale in Australia within 12 months may, under section 707 of the Corporations Act, require disclosure to investors under Chapter 6D.2 if none of the exemptions in section 708 applies to that resale. By applying for the shares you undertake to us that you will not, for a period of 12 months from the date of issue of the shares, offer, transfer, assign or otherwise alienate those shares to investors in Australia except in circumstances where disclosure to investors is not required under Chapter 6D.2 of the Corporations Act or where a compliant disclosure document is prepared and lodged with the ASIC.

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#### Notice to prospective investors in Japan
The shares have not been and will not be registered pursuant to Article 4, Paragraph 1 of the Financial Instruments and Exchange Act. Accordingly, none of the shares or any interest therein may be offered or sold, directly or indirectly, in Japan or to, or for the benefit of, any "resident" of Japan (which term as used herein means any person resident in Japan, including any corporation or other entity organized under the laws of Japan), or to others for re-offering or resale, directly or indirectly, in Japan or to or for the benefit of a resident of Japan, except pursuant to an exemption from the registration requirements of, and otherwise in compliance with, the Financial Instruments and Exchange Act and any other applicable laws, regulations and ministerial guidelines of Japan in effect at the relevant time.

#### Notice to prospective investors in Hong Kong
The shares have not been offered or sold and will not be offered or sold in Hong Kong, by means of any document, other than (a) to "professional investors" as defined in the Securities and Futures Ordinance (Cap. 571 of the Laws of Hong Kong) of Hong Kong (the "SFO") and any rules made thereunder or (b) in other circumstances which do not result in the document being a "prospectus" as defined in the Companies (Winding Up and Miscellaneous Provisions) Ordinance (Cap. 32) of Hong Kong (the "CO") or which do not constitute an offer to the public within the meaning of the CO. No advertisement, invitation, or document relating to the shares has been or may be issued or has been or may be in the possession of any person for the purposes of issue, whether in Hong Kong or elsewhere, which is directed at, or the contents of which are likely to be accessed or read by, the public of Hong Kong (except if permitted to do so under the securities laws of Hong Kong) other than with respect to shares which are or are intended to be disposed of only to persons outside Hong Kong or only to "professional investors" as defined in the SFO and any rules made thereunder.

#### Notice to prospective investors in Singapore
Each joint book-running manager has acknowledged that this prospectus supplement has not been registered as a prospectus with the Monetary Authority of Singapore. Accordingly, each joint book-running manager has represented and agreed that it has not offered or sold any shares or caused the shares to be made the subject of an invitation for subscription or purchase and will not offer or sell any shares or cause the shares to be made the subject of an invitation for subscription or purchase, and has not circulated or distributed, nor will it circulate or distribute, this prospectus supplement or any other document or material in connection with the offer or sale, or invitation for subscription or purchase, of the shares, whether directly or indirectly, to any person in Singapore other than:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; (a)

to an institutional investor (as defined in Section 4A of the Securities and Futures Act (Chapter 289) of Singapore, as modified or amended from time to time (the "SFA")) pursuant to Section 274 of the SFA;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; (b)

to a relevant person (as defined in Section 275(2) of the SFA) pursuant to Section 275(1) of the SFA, or any person pursuant to Section 275(1A) of the SFA, and in accordance with the conditions specified in Section 275 of the SFA; or

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; (c)

otherwise pursuant to, and in accordance with the conditions of, any other applicable provision of the SFA.

Where the shares are subscribed or purchased under Section 275 of the SFA by a relevant person which is (a) a corporation (which is not an accredited investor (as defined in Section 4A of the SFA)) the sole business of which is to hold investments and the entire share capital of which is owned by one or more individuals, each of whom is an accredited investor, or (b) a trust (where the trustee is not an accredited investor) whose sole purpose is to hold investments and each beneficiary of the trust is an individual who is an accredited investor, securities or securities-based derivatives contracts (each term as defined in Section 2(1) of the SFA) of that corporation or the beneficiaries' rights and interest (howsoever described) in that trust shall not be transferred within six months after that corporation or that trust has acquired the shares pursuant to an offer made under Section 275 of the SFA except:

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; (i)

to an institutional investor or to a relevant person, or to any person arising from an offer referred to in Section 275(1A) or Section 276(4)(i)(B) of the SFA;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; (ii)

where no consideration is or will be given for the transfer;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; (iii)

where the transfer is by operation of law;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; (iv)

as specified in Section 276(7) of the SFA; or

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; (v)

as specified in Regulation 37A of the Securities and Futures (Offers of Investments) (Securities and Securities-based Derivatives Contracts) Regulations 2018.

*Singapore SFA product classification*. In connection with Section 309B of the SFA and the CMP Regulations 2018, unless otherwise specified before an offer of shares, we have determined, and hereby notify all relevant persons (as defined in Section 309A(1) of the SFA), that the shares are "prescribed capital markets products" (as defined in the CMP Regulations 2018) and Excluded Investment Products (as defined in MAS Notice SFA 04-N12: Notice on the Sale of Investment Products and MAS Notice FAA-N16: Notice on Recommendations on Investment Products).

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#### LEGAL MATTERS
The validity of the shares of common stock offered by this prospectus supplement will be passed upon for us by Simpson Thacher & Bartlett LLP. Certain legal matters in connection with the offering will be passed upon for the underwriter by Latham & Watkins LLP.

#### EXPERTS
The consolidated financial statements of Waystar Holding Corp. as of December 31, 2024 and 2023, and for each of the years in the three-year period ended December 31, 2024, have been incorporated by reference herein in reliance upon the report of KPMG LLP, independent registered public accounting firm, incorporated by reference herein, and upon the authority of said firm as experts in accounting and auditing.

#### WHERE YOU CAN FIND MORE INFORMATION
We have filed a registration statement on Form S-3 under the Securities Act with respect to the common stock offered by this prospectus supplement with the SEC. This prospectus supplement and the accompanying prospectus are part of the registration statement and therefore do not contain all of the information set forth in the registration statement and its exhibits and schedules, portions of which have been omitted as permitted by the rules and regulations of the SEC. For further information about us and our common stock, you should refer to the registration statement and its exhibits and schedules. Statements contained in this prospectus supplement and the accompanying prospectus regarding the contents of any contract or other document referred to in those documents are not necessarily complete, and in each instance we refer you to the copy of the contract or other document filed as an exhibit to the registration statement or other document. Each of these statements is qualified in all respects by this reference.

We are subject to the informational reporting requirements of the Exchange Act and, in accordance with the Exchange Act, we file annual, quarterly and current reports, proxy statements, and other information with the SEC. Our filings with the SEC are available to the public on the SEC's website at http://www.sec.gov. Those filings are also available to the public on, or accessible through, our website (www.waystar.com) under the heading "Investor Relations." The information we file with the SEC or contained on or accessible through our corporate website or any other website that we may maintain is not part of this prospectus supplement or the registration statement of which this prospectus supplement is a part.

We intend to make available to our common stockholders annual reports containing financial statements audited by an independent registered public accounting firm.

#### INCORPORATION BY REFERENCE
The rules of the SEC allow us to incorporate by reference information we file with the SEC. This means that we are disclosing important information to you by referring to other documents. The information incorporated by reference is considered to be part of this prospectus supplement. To the extent there are inconsistencies between the information contained in this prospectus supplement and the information contained in the documents filed with the SEC prior to the date of this prospectus supplement and incorporated by reference, the information in this prospectus supplement shall be deemed to supersede the information in such incorporated documents. We incorporate by reference the documents listed below (other than any portions thereof, which under the Exchange Act, and applicable SEC rules, are not deemed "filed" under the Exchange Act):

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • [our Annual Report on Form 10-K for the year ended December 31, 2024;](https://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000141057825000148/way-20241231x10k.htm)

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our Quarterly Reports on Form 10-Q for the quarterly periods ended [March 31, 2025](https://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000141057825001048/way-20250331x10q.htm) and [June 30, 2025](https://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000199035425000012/way-20250630.htm), filed with the SEC on April 30, 2025 and July 30, 2025;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the information specifically incorporated by reference into our [Annual Report on Form 10-K for the fiscal year ended December 31, 2024](https://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000141057825000148/way-20241231x10k.htm) from our [Definitive Proxy Statement on Schedule 14A filed on April 29, 2025](https://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000110465925041369/tm253417-5_def14a.htm); and

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our Current Reports on Form 8-K, filed with the SEC on [May 12, 2025](https://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000110465925047008/tm2514730d1_8k.htm), [June 5, 2025](https://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000110465925056893/tm2517226d1_8k.htm), [July 23, 2025](https://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000110465925070034/tm2521498d1_8k.htm) (only with respect to Item 1.01 and Exhibits 2.1, 10.1, 10.2, and 10.3 of Item 9.01), and [August 12, 2025](https://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000199035425000015/way-20250812.htm) (only with respect to Items 1.01 and 2.03 and Exhibit 10.1 of Item 9.01).

If we have incorporated by reference any statement or information in this prospectus supplement and we subsequently modify that statement or information with information contained in this prospectus supplement, the statement or information previously incorporated in this prospectus supplement is also modified or superseded in the same manner.

We will provide without charge to each person to whom a copy of this prospectus supplement has been delivered, a copy of any and all of these filings. You may request a copy of these filings by writing to us at:

Investor Relations

Waystar Holding Corp.

1550 Digital Drive, #300

Lehi, Utah 84043

e-mail: investors@waystar.com

Exhibits to any documents incorporated by reference in this prospectus supplement will not be sent, however, unless those exhibits have been specifically referenced in this prospectus supplement.

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#### PROSPECTUS

### 75,664,799 Shares
![[MISSING IMAGE: lg_waystar-4c.jpg]](lg_waystar-4c.jpg)

### Waystar Holding Corp.

### Common Stock
This prospectus relates to the offer and sale from time to time of up to 75,664,799 shares of Waystar Holding Corp. common stock, $0.01 par value per share, by the selling stockholders identified in this prospectus or in supplements to this prospectus. See "Selling Stockholders." The registration of the shares of common stock to which this prospectus relates does not require the selling stockholders to sell any of their shares of our common stock.

We will not receive any proceeds from the sale of the shares by the selling stockholders, but we have agreed to pay certain registration expenses, other than underwriting discounts and commissions. The selling stockholders from time to time may offer and sell the shares held by them directly or through underwriters, agents or broker-dealers on terms to be determined at the time of sale, as described in more detail in this prospectus. For more information, see "Plan of Distribution."

Our common stock is listed on The Nasdaq Global Select Market ("Nasdaq") under the symbol "WAY." On July 14, 2025, the last reported sale price of our common stock as reported on Nasdaq was $38.35 per share.

 **Investing in our common stock involves risks. Before making a decision to invest in our common stock, you should refer to the risk factors included in our periodic reports, in any applicable prospectus supplements relating to specific offerings and in other information that we file with the Securities and Exchange Commission (the "SEC") that is incorporated by reference herein or therein. See "Risk Factors" on page [6](#tRIFA) of this prospectus.** 

 **Neither the SEC nor any state securities commission has approved or disapproved of these securities or passed upon the accuracy or adequacy of this prospectus. Any representation to the contrary is a criminal offense.** 

#### Prospectus dated July 14, 2025.

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#### **TABLE OF CONTENTS**

---

| | |
|:---|:---|
| | **Page**  |
| [Prospectus Summary](#tPRSU)  | [1](#tPRSU) |
| [Risk Factors](#tRIFA)  | [6](#tRIFA) |
| [Special Note Regarding Forward-Looking Statements](#tSNRF)  | [7](#tSNRF) |
| [Use of Proceeds](#tUOP)  | [10](#tUOP) |
| [Selling Stockholders](#tSEST)  | [11](#tSEST) |
| [Description of Capital Stock](#tDOCS)  | [13](#tDOCS) |
| [Certain United States Federal Income Tax Consequences to Non-U.S. Holders](#tCUSF)  | [22](#tCUSF) |
| [Plan of Distribution](#tPOD)  | [25](#tPOD) |
| [Legal Matters](#tLEMA)  | [27](#tLEMA) |
| [Experts](#tEXP)  | [27](#tEXP) |
| [Where You Can Find More Information](#tWYCF)  | [28](#tWYCF) |
| [Information Incorporated by Reference](#tIIBR)  | [28](#tIIBR) |

---

 **You should rely only on the information contained or incorporated by reference in this prospectus, any amendment or supplement to this prospectus, or any free writing prospectus we may authorize to be delivered or made available to you. Neither we nor the selling stockholders or the underwriters, if any, have authorized anyone to provide you with information or to make any representations different from those contained or incorporated by reference in this prospectus, any amendment or supplement to this prospectus, or any free writing prospectus prepared by us or on our behalf. Neither we nor the selling stockholders or the underwriters, if any, take any responsibility for, or can provide any assurance as to the reliability of, any information other than the information contained or incorporated by reference in this prospectus, any amendment or supplement to this prospectus, or any free writing prospectus prepared by us or on our behalf. This prospectus, any amendment or supplement to this prospectus, or any applicable free writing prospectus is an offer to sell only the shares of common stock offered hereby from time to time, but only under circumstances where it is lawful to do so. The selling stockholders are not offering to sell shares of our common stock in any jurisdiction where an offer or sale is not permitted. The information contained in or incorporated by reference in this prospectus is accurate only as of the date of this prospectus, regardless of the time of delivery of this prospectus, any amendment or supplement to this prospectus, or any applicable free writing prospectus, as the case may be, or any sale of shares of our common stock. Our business, results of operations, and financial condition may have changed since such date.** 

This prospectus is part of a registration statement on Form S-3 that we have filed with the SEC using a "shelf" registration process. Under the shelf registration process, the selling stockholders may, from time to time, offer and sell the shares of common stock described in this prospectus and in any accompanying prospectus supplement in one or more transactions. This prospectus provides you with a general description of the shares of common stock the selling stockholders may offer. Each time the selling stockholders sell shares of our common stock using this prospectus, to the extent necessary, we will provide a prospectus supplement that will contain specific information about the terms of that offering, including the number of shares being offered, the manner of distribution, the identity of any underwriters or other counterparties, and other specific terms related to the offering. We may also authorize one or more free writing prospectuses to be provided to you that may contain material information relating to these offerings. The prospectus supplement may also add, update, or change information contained or incorporated by reference in this prospectus. To the extent that any statement made in an accompanying prospectus supplement or free writing prospectus is inconsistent with statements made in this prospectus, the statements made in this prospectus will be deemed modified or superseded by those made in the accompanying prospectus supplement or free writing prospectus, as the case may be. You should read both this prospectus and any prospectus supplement together, along with the information incorporated by reference herein or therein and any free writing prospectus prepared by us or on our behalf.

i

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For investors outside of the United States, neither we nor the selling stockholders or the underwriters, if any, have done anything that would permit an offering of shares of our common stock or the possession or distribution of this prospectus, any amendment or supplement to this prospectus, or any applicable free writing prospectus, in any jurisdiction where action for that purpose is required, other than in the United States. You are required to inform yourselves about and to observe any restrictions relating to an offering of shares of common stock and the possession or distribution of this prospectus, any amendment or supplement to this prospectus, or any applicable free writing prospectus outside of the United States.

#### Industry and Market Data
This prospectus incorporates by reference, and any prospectus supplement or free writing prospectus may contain or incorporate by reference, market data and industry statistics and forecasts that are based on independent industry publications and other publicly available information. Although we believe these sources are reliable, neither we nor the selling stockholders or the underwriters, if any, can guarantee the accuracy or completeness of this information and we have not independently verified this information. In addition, the market and industry data and forecasts that may be included or incorporated by reference in this prospectus, any prospectus supplement, or any applicable free writing prospectus may involve estimates, assumptions, and other risks and uncertainties and are subject to change based on various factors, including those discussed under the heading "Risk Factors" in this prospectus, and under similar headings in other documents that are incorporated by reference herein. Accordingly, investors should not place undue reliance on this information.

#### Trademarks, Service Marks, Tradenames, and Copyrights
We own a number of registered and common law trademarks and pending applications for trademark registrations in the United States. Unless otherwise indicated, all trademarks, service marks, trade names, and copyrights appearing in this prospectus or incorporated by reference herein are proprietary to us, our affiliates, and/or licensors. This prospectus and the documents incorporated by reference herein also contain trademarks, tradenames, service marks, and copyrights of third parties, which are the property of their respective owners. Solely for convenience, the trademarks, tradenames, service marks, and copyrights referred to in this prospectus and in the information incorporated by reference herein may appear without the <sup>®</sup>, <sup>TM</sup>, <sup>SM</sup>, or <sup>©</sup> symbols, but such references are not intended to indicate, in any way, that we will not assert, to the fullest extent under applicable law, our rights or the rights of the applicable licensors to these trademarks, tradenames, service marks, and copyrights. We do not intend our use or display of other parties' trademarks, tradenames, service marks, or copyrights to imply, and such use or display should not be construed to imply, a relationship with, or endorsement or sponsorship of us by, these other parties.

#### Basis of Presentation
The following terms are used in this prospectus and have the following meanings unless otherwise noted or indicated by the context:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • "Bain" means those certain investment funds of Bain Capital, LP and its affiliates;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • "CPPIB" means Canada Pension Plan Investment Board;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • "DGCL" means the Delaware General Corporation Law, as amended;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • "EQT" means those certain investment funds of EQT AB and its affiliates;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • "Exchange Act" means the U.S. Securities Exchange Act of 1934, as amended;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • "Institutional Investors" means EQT, CPPIB, and Bain, and their respective affiliates;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • "SEC" means the U.S. Securities and Exchange Commission;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • "Securities Act" means the U.S. Securities Act of 1933, as amended;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • "selling stockholders" means Derby LuxCo S.à r.l., CPP Investment Board Private Holdings (4) Inc., BCPE Derby Investor, LP., and BCPE Derby (DE) SPV;

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • "Stockholders Agreement" means the stockholders agreement, dated as of June 10, 2024, as amended as of April 10, 2025, by and among the Institutional Investors, certain stockholders, and certain members of management; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • "Waystar," the "Company," "we," "us," and "our" mean the business of Waystar Holding Corp. and its subsidiaries.

Numerical figures included in this prospectus or in the documents incorporated by reference herein have been subject to rounding adjustments. Accordingly, numerical figures shown as totals in various tables may not be arithmetic aggregations of the figures that precede them.

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#### PROSPECTUS SUMMARY
 *This summary highlights information contained elsewhere or incorporated by reference in this prospectus or any prospectus supplement and does not contain all of the information you should consider before investing in shares of our common stock. You should read this entire prospectus, any applicable prospectus supplement, and the documents incorporated herein or therein carefully, including the section entitled "Risk Factors" and the financial statements and the related notes incorporated by reference into this prospectus, before you decide to invest in shares of our common stock.* 

 *Unless otherwise indicated or the context otherwise requires, references in this prospectus to the "Company," "Waystar," "we," "us," and "our" means Waystar Holding Corp. and its consolidated subsidiaries.* 

#### Our Company
Our mission is to simplify healthcare payments through our modern cloud-based software, enabling our healthcare clients to prioritize patient care and optimize their financial performance.

Waystar provides healthcare organizations with mission-critical cloud software that simplifies healthcare payments. Our enterprise-grade platform streamlines the complex and disparate processes our healthcare provider clients must manage to be reimbursed correctly, while improving the payments experience for providers, patients, and payers. We leverage internally developed artificial intelligence ("AI") as well as proprietary, advanced algorithms to automate payment-related workflow tasks and drive continuous improvement, which enhances claim and billing accuracy, enriches data integrity, and reduces labor costs for providers.

Put simply, our software helps providers get paid faster, accurately, and more efficiently, while ensuring patients receive a modern, transparent, and consumer-friendly financial experience.

The healthcare payment ecosystem is highly complex, beginning with pre-service patient onboarding and extending through post-service revenue collection, with dozens of interdependent steps in between. Within this multi-step workflow, the process for determining how much a provider should be reimbursed involves millions of permutations of variables, such as over 10,000 diagnosis codes that are constantly changing and unique payer contracts, each with individual rules, processes, and reimbursement requirements. The burden borne by providers of tracking and managing all of these variables, coupled with a constantly evolving regulatory framework, often results in incorrect payments or denials that require time-consuming appeals procedures to resolve. Historically, healthcare providers have relied upon a patchwork of manual processes and systems to navigate these complexities and support their payment functions. However, this legacy approach has resulted in workflow delays, lost revenue, and slower time to payment. Our purpose- built software platform addresses these challenges and optimizes healthcare payments across all stages of the patient journey. Our clients utilize our software to manage pre-encounter workflows such as eligibility checks and prior authorization approvals, as well as mid- and post-encounter workflows such as co-pay collection, claims submission and monitoring, and payer remittances.

Our software is used daily by providers of all types and sizes across the continuum of care, including physician practices, clinics, surgical centers, and laboratories, as well as large hospitals and health systems. We currently serve over 30,000 clients of various sizes, representing over one million distinct providers practicing across a variety of care sites, including 16 of the top 20 U.S. News Best Hospitals. Our client base is highly diversified, and for the year ended December 31, 2024, our top 10 clients accounted for only 11.2% of our total revenue for such period. Our business model is designed such that as our clients grow to serve more patients, their claims and transactional volumes increase, resulting in corresponding growth in our business. In addition, our clients frequently adopt a greater number of our solutions over time and introduce our solutions across new sites of care. In 2024, we facilitated over six billion healthcare payments transactions, including over $1.8 trillion in gross claims volume. As of 2023, we facilitated healthcare payments transactions spanning approximately 50% of patients in the United States.

Our platform benefits from powerful network effects. Our cloud-based software is driven by a sophisticated, automated, and curated rules engine, employing AI to generate and incorporate real-time feedback from millions of network transactions processed through our platform each day. Every transaction we process provides additional data insights across providers, patients, and payers, which are embedded in

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updates that are deployed efficiently across our client base. This results in cumulative benefits to us over time — as we capture more data from each transaction we process, we leverage that data to continue to improve the Waystar platform through embedded machine learning, advanced algorithms, and other in-house AI technologies to deliver added value to our clients. In turn, the more value we create for our clients, the more likely it is that they will continue to use our products, allowing us to continue to capture more data that results in tangible improvements to our platform. As a result, our clients benefit from faster and more efficient performance from software that is evolving to meet ever-changing regulatory and payer requirements, enabling accurate and timely reimbursement.

For a description of our business, financial condition, results of operations, and other important information regarding Waystar, we refer you to our filings with the SEC incorporated by reference in this prospectus. For instructions on how to find copies of these documents, see "Where You Can Find More Information." We were originally incorporated in Delaware on August 13, 2019 and subsequently changed our name to Waystar Holding Corp. on August 11, 2023. Our principal offices are located at 1550 Digital Drive, #300, Lehi, Utah 84043 and 9901 Linn Station Road, Louisville, Kentucky 40223. Our telephone number is (844) 492-9782. We maintain a website at waystar.com. The reference to our website is intended to be an inactive textual reference only. The information contained on, or that can be accessed through, our website is not part of this prospectus.

#### Summary of Risk Factors
Investing in our common stock involves a high degree of risk. You should carefully consider all of the risks described in "Risk Factors" elsewhere in this prospectus, in our [Annual Report on Form 10-K for the fiscal year ended December 31, 2024 ("Annual Report on Form 10-K"),](https://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000141057825000148/way-20241231x10k.htm) and our subsequent Quarterly Reports on Form 10-Q, which are incorporated by reference herein, before deciding to invest in our common stock. If any of the risks actually occur, our business, results of operations, prospects, and financial condition may be materially adversely affected. In such case, the trading price of our common stock may decline, and you may lose part or all of your investment. Below is a summary of some of the principal risks we face:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our operation in a highly competitive industry;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our ability to retain our existing clients and attract new clients;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our ability to successfully execute on our business strategies in order to grow;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our ability to accurately assess the risks related to acquisitions and successfully integrate acquired businesses;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our ability to establish and maintain strategic relationships;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the growth and success of our clients and overall healthcare transaction volumes;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • consolidation in the healthcare industry;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our selling cycle of variable length to secure new client agreements;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our implementation cycle that is dependent on our clients' timing and resources;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our dependence on our senior management team and certain key employees, and our ability to attract and retain highly skilled employees;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the accuracy of the estimates and assumptions we use to determine the size of our total addressable market;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our ability to develop and market new solutions, or enhance our existing solutions, to respond to technological changes or evolving industry standards;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the interoperability, connectivity, and integration of our solutions with our clients' and their vendors' networks and infrastructures;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the performance and reliability of internet, mobile, and other infrastructure;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the consequences if we cannot obtain, process, use, disclose, or distribute the highly regulated data we require to provide our solutions;

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

&nbsp;&nbsp;&nbsp;&nbsp;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our reliance on certain third-party vendors and providers;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • any errors or malfunctions in our products and solutions;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • failure by our clients to obtain proper permissions or provide us with accurate and appropriate information;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the potential for embezzlement, identity theft, or other similar illegal behavior by our employees or vendors and a failure of our employees or vendors to observe quality standards or adhere to environmental, social, and governance standards;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our compliance with the applicable rules of the National Automated Clearing House Association ("NACHA") and the applicable requirements of card networks;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • increases in card network fees and other changes to fee arrangements;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the effect of payer and provider conduct which we cannot control;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • privacy concerns and security breaches or incidents relating to our platform or data (including personal information and other regulated data);

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the complex and evolving laws and regulations regarding privacy, data protection, and cybersecurity;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our ability to adequately protect and enforce our intellectual property rights;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our ability to use or license data and integrate third-party technologies;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our use of "open source" software;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • legal proceedings initiated by third parties alleging that we are infringing or otherwise violating their intellectual property rights;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • claims that our employees, consultants, or independent contractors have wrongfully used or disclosed confidential information of third parties;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the heavily regulated industry in which we conduct business;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the uncertain and evolving healthcare regulatory and political framework;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • health care laws and data privacy and security laws and regulations governing our processing of personal information;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • reduced revenues in response to changes to the healthcare regulatory landscape;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • legal, regulatory, and other proceedings that could result in adverse outcomes;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • consumer protection laws and regulations;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • contractual obligations requiring compliance with certain provisions of the Bank Secrecy Act ("BSA") and Anti- Money Laundering ("AML") laws and regulations;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • existing laws that regulate our ability to engage in certain marketing activities;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our full compliance with website accessibility standards;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • any changes in our tax rates, the adoption of new tax legislation, or exposure to additional tax liabilities;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • limitations on our ability to use our net operating losses ("NOLs") to offset future taxable income;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • losses due to asset impairment charges;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • restrictive covenants in the agreements governing our credit facilities;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • interest rate fluctuations;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • unavailability of additional capital on acceptable terms or at all;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the impact of general macroeconomic conditions;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our history of net losses and our ability to achieve or maintain profitability;

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

&nbsp;&nbsp;&nbsp;&nbsp;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the interests of the Institutional Investors may be different than the interests of other holders of our securities;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our status as an "emerging growth company" and whether the reduced disclosure requirements applicable to "emerging growth companies" will make our common stock less attractive to investors; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the other factors discussed under "Risk Factors" in this prospectus and our Annual Report on

Form 10-K.

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#### The Offering
Common Stock Offered by the Selling Stockholders

Up to 75,664,799 shares of common stock.

Common Stock Outstanding as of June 30, 2025

174,146,070 shares of common stock.

Does not reflect 3,820,546 shares of common stock underlying restricted stock units outstanding; 14,981,933 shares of common stock issuable upon exercise of outstanding stock options; up to 792,394 shares of common stock issuable upon the vesting of outstanding performance stock units; 5,489,286 shares of common stock available for future issuance under the Company's 2024 Equity Incentive Plan; and 3,250,000 shares of common stock available for future issuance under the Company's 2024 Employee Stock Purchase Plan.

Use of Proceeds

The selling stockholders will receive all of the proceeds of the sale of shares of common stock offered from time to time pursuant to this prospectus. Accordingly, we will not receive any proceeds from the sale of shares of common stock that may be sold from time to time pursuant to this prospectus.

Dividend Policy

We have no current plans to pay dividends on our common stock. Any decision to declare and pay dividends in the future will be made at the sole discretion of our board of directors and will depend on, among other things, our results of operations, cash requirements, financial condition, legal, tax, regulatory, and contractual restrictions, including restrictions in the agreements governing our indebtedness, and other factors that our board of directors may deem relevant.

Risk Factors

Investing in our common stock involves a high degree of risk. Before making a decision to invest in our common stock, you should refer to the risk factors contained in or incorporated by reference under "Risk Factors" on page 6 of this prospectus and under similar headings in other documents that are incorporated by reference herein.

Nasdaq Symbol

"WAY"

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#### RISK FACTORS
Investing in our common stock involves risks. You should carefully consider the risks and uncertainties described in our most recent Annual Report on Form 10-K and our subsequent Quarterly Reports on Form 10-Q, which are incorporated by reference herein, as the same may be updated from time to time by our subsequent filings under the Securities Exchange Act of 1934, as amended (the "Exchange Act"). You should also carefully consider the other information contained in this prospectus, as updated by our subsequent filings under the Exchange Act, and the risk factors and other information contained in any applicable prospectus supplement or free writing prospectus, before acquiring any shares of our common stock. These risks could materially affect our business, results of operations, or financial condition, and cause the value of our common stock to decline. You could lose all or part of your investment.

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#### SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS
This prospectus includes and incorporates by reference forward-looking statements, within the meaning of Section 27A of the Securities Act of 1933, as amended (the "Securities Act"), Section 21E of the Exchange Act, and the Private Securities Litigation Reform Act of 1995, that reflect our current views with respect to, among other things, our operations and financial performance. Forward-looking statements include all statements that are not historical facts. These forward-looking statements are included in or incorporated by reference into this prospectus and relate to matters such as our industry, business strategy, goals, and expectations concerning our market position, future operations, margins, profitability, capital expenditures, liquidity, and capital resources and other financial and operating information. We have used the words "anticipate," "assume," "believe," "continue," "could," "estimate," "expect," "intend," "may," "plan," "potential," "predict," "project," "future," "will," "seek," "foreseeable," the negative version of these words, or similar terms and phrases to identify forward-looking statements in this prospectus.

The forward-looking statements contained in or incorporated by reference into this prospectus are based on management's current expectations and are not guarantees of future performance. The forward-looking statements are subject to various risks, uncertainties, assumptions, or changes in circumstances that are difficult to predict or quantify. Our expectations, beliefs, and projections are expressed in good faith and we believe there is a reasonable basis for them. However, there can be no assurance that management's expectations, beliefs, and projections will result or be achieved. Actual results may differ materially from these expectations due to changes in global, regional, or local economic, business, competitive, market, regulatory, and other factors, many of which are beyond our control. These factors include but are not limited to the following:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our operation in a highly competitive industry;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our ability to retain our existing clients and attract new clients;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our ability to successfully execute on our business strategies in order to grow;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our ability to accurately assess the risks related to acquisitions and successfully integrate acquired businesses;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our ability to establish and maintain strategic relationships;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the growth and success of our clients and overall healthcare transaction volumes;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • consolidation in the healthcare industry;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our selling cycle of variable length to secure new client agreements;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our implementation cycle that is dependent on our clients' timing and resources;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our dependence on our senior management team and certain key employees, and our ability to attract and retain highly skilled employees;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the accuracy of the estimates and assumptions we use to determine the size of our total addressable market;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our ability to develop and market new solutions, or enhance our existing solutions, to respond to technological changes, or evolving industry standards;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the interoperability, connectivity, and integration of our solutions with our clients' and their vendors' networks and infrastructures;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the performance and reliability of internet, mobile, and other infrastructure;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the consequences if we cannot obtain, process, use, disclose, or distribute the highly regulated data we require to provide our solutions;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our reliance on certain third-party vendors and providers;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • any errors or malfunctions in our products and solutions;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • failure by our clients to obtain proper permissions or provide us with accurate and appropriate information;

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the potential for embezzlement, identity theft, or other similar illegal behavior by our employees or vendors, and a failure of our employees or vendors to observe quality standards or adhere to environmental, social, and governance standards;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our compliance with the applicable rules of NACHA and the applicable requirements of card networks;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • increases in card network fees and other changes to fee arrangements;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the effect of payer and provider conduct which we cannot control;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • privacy concerns and security breaches or incidents relating to our platform;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the complex and evolving laws and regulations regarding privacy, data protection, and cybersecurity;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our ability to adequately protect and enforce our intellectual property rights;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our ability to use or license data and integrate third-party technologies;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our use of "open source" software;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • legal proceedings initiated by third parties alleging that we are infringing or otherwise violating their intellectual property rights;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • claims that our employees, consultants, or independent contractors have wrongfully used or disclosed confidential information of third parties;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the heavily regulated industry in which we conduct business;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the uncertain and evolving healthcare regulatory and political framework;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • health care laws and data privacy and security laws and regulations governing our processing of personal information;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • reduced revenues in response to changes to the healthcare regulatory landscape;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • legal, regulatory, and other proceedings that could result in adverse outcomes;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • consumer protection laws and regulations;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • contractual obligations requiring compliance with certain provisions of BSA/AML laws and regulations;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • existing laws that regulate our ability to engage in certain marketing activities;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our full compliance with website accessibility standards;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • any changes in our tax rates, the adoption of new tax legislation, or exposure to additional tax liabilities;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • limitations on our ability to use our NOLs to offset future taxable income;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • losses due to asset impairment charges;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • restrictive covenants in the agreements governing our credit facilities;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • interest rate fluctuations;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • unavailability of additional capital on acceptable terms or at all;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the impact of general macroeconomic conditions;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our history of net losses and our ability to achieve or maintain profitability;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the interests of the Institutional Investors may be different than the interests of other holders of our securities; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the other factors disclosed or incorporated by reference in this prospectus.

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These factors should not be construed as exhaustive and should be read in conjunction with the other cautionary statements that are included in or incorporated by reference into this prospectus. Should one or more of these risks or uncertainties materialize, or should any of our assumptions prove incorrect, our actual results may vary in material respects from those projected in these forward-looking statements.

Any forward-looking statements made by us in or incorporated by reference into this prospectus speak only as of the date of this prospectus or the document incorporated or deemed incorporated by reference herein and are expressly qualified in their entirety by the cautionary statements included in or incorporated by reference into this prospectus. Factors or events that could cause our actual results to differ may emerge from time to time, and it is not possible for us to predict all of them. You should not place undue reliance on our forward-looking statements. We undertake no obligation to publicly update or review any forward-looking statement, whether as a result of new information, future developments, or otherwise, except as may be required by any applicable securities laws.

Investors and others should note that we routinely announce financial and other material information using our Investor Relations website (investors.waystar.com), SEC filings, press releases, public conference calls, and webcasts. We use these channels of distribution to communicate with our investors and members of the public about our company, our services, and other items of interest. Information contained on our website is not part of this prospectus or our other filings with the SEC.

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#### USE OF PROCEEDS
The selling stockholders will receive all of the proceeds of the sale of shares of common stock offered from time to time pursuant to this prospectus. Accordingly, we will not receive any proceeds from the sale of shares of common stock that may be sold from time to time pursuant to this prospectus.

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#### SELLING STOCKHOLDERS
On June 10, 2024, we completed our initial public offering (our "IPO"). In connection with our IPO, we entered into an amended and restated registration rights agreement with the Institutional Investors and the other parties thereto providing them with certain registration rights with respect to our common stock. This prospectus covers 75,664,799 shares of our common stock that may be offered for resale by the selling stockholders. For more information about our relationships with the selling stockholders and their affiliates, see the section entitled "Certain Relationships and Related-Party Transactions" in our [Definitive Proxy Statement on Schedule 14A filed on April 29, 2025](https://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000110465925041369/tm253417-5_def14a.htm), which is incorporated herein by reference.

The following table sets forth information as of June 30, 2025, with respect to the selling stockholders and the shares of our common stock beneficially owned by the selling stockholders that may from time to time be offered or sold pursuant to this prospectus. Beneficial ownership is determined in accordance with the rules of the SEC. Information concerning the selling stockholders may change from time to time, and any changed information will be set forth in supplements to this prospectus or a post-effective amendment to the registration statement to which this prospectus relates if and when necessary. The selling stockholders may offer all, some or none of their shares of common stock. We cannot advise you as to whether the selling stockholders will in fact sell any or all of such shares of common stock. In addition, the selling stockholders may have sold or transferred, in transactions pursuant to this prospectus or otherwise, some or all of their shares since the date as of which the information is presented in the table below. Information concerning the selling stockholders may change from time to time and any such changed information will, if required, be set forth in supplements to this prospectus or post-effective amendments to the registration statement of which this prospectus is a part, as may be appropriate.

All percentages in the table are based on 174,146,070 shares of common stock outstanding as of June 30, 2025.

---

| | | | | | |
|:---|:---|:---|:---|:---|:---|
| | **Shares of Common Stock <br> Beneficially Owned**  | **Shares of Common Stock <br> Beneficially Owned**  | **Shares of <br> Common Stock <br> that May be <br> Offered for <br> Resale**  | **Shares of Common <br> Stock Beneficially <br> Owned After the Sale <br> of the Maximum <br> Number of Shares of <br> Common Stock**  | **Shares of Common <br> Stock Beneficially <br> Owned After the Sale <br> of the Maximum <br> Number of Shares of <br> Common Stock**  |
| **Name**  | **Number of <br> Shares**  | **Percent of <br> Common <br> Stock <br> Outstanding**  | **Shares of <br> Common Stock <br> that May be <br> Offered for <br> Resale**  | **Number of <br> Shares**  | **Percent of <br> Common <br> Stock <br> Outstanding**  |
| EQT<sup>(1)</sup> | 32645525 | 18.7% | 32645525 |  |  |
| CPPIB<sup>(2)</sup> | 24964225 | 14.3% | 24964225 |  |  |
| Bain<sup>(3)</sup> | 18055049 | 10.4% | 18055049 |  |  |

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(1) Consists of shares of common stock held directly by Derby LuxCo S.à r.l. ("Derby LuxCo"). Several investment vehicles collectively make up the fund known as "EQT VIII." EQT VIII owns 100% of the membership interests in Derby LuxCo. EQT Fund Management S.à r.l. ("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 that acts by majority approval. The individual members of such board are Sara Huda, Magnus Sjöcrona, Leif Patrik Burnäs, Peter Veldman, and Christiaan Snyders. The registered address of EFMS and Derby LuxCo is 51A, Boulevard Royal, L-2449 Luxembourg, Grand Duchy of Luxembourg.

(2) CPPIB, through its wholly-owned subsidiary CPP Investment Board Private Holdings (4) Inc., beneficially owns 24,964,225 shares of common stock. Investment and voting power with regard to shares held by CPP Investment Board Private Holdings (4) Inc. rests with CPPIB. John Graham is the President and Chief Executive Officer of CPPIB and, in such capacity, may be deemed to have voting and dispositive power with respect to the shares of common stock beneficially owned by CPPIB. Mr. Graham disclaims beneficial ownership over any such shares. The address of CPPIB is One Queen Street East, Suite 2500, Toronto, Ontario, M5C 2W5, Canada.

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

(3) Consists of 2,609,155 shares of common stock held directly by BCPE Derby Investor, LP ("BCPE Derby") and 15,445,894 shares of common stock held directly by BCPE Derby (DE) SPV, LP ("BCPE Derby SPV"). Bain Capital Investors, LLC ("BCI") is the manager of Bain Capital Partners XI, LP, which is the general partner of Bain Capital Fund XI, LP ("Fund XI"). Fund XI is the (i) sole member of BCPE Derby GP, LLC, which is the general partner of BCPE Derby and (ii) sole member of BCPE Derby (DE) SPV, LLC, which is the general partner of BCPE Derby SPV. As a result, BCI may be deemed to share voting and dispositive power with respect to the shares held by BCPE Derby and BCPE Derby SPV. Voting and investment decisions with respect to securities held BCPE Derby and BCPE Derby SPV are made by the partners of BCI, of whom there are three or more and none of whom individually has the power to direct such decisions. The address of BCPE Derby and BCPE Derby SPV is c/o Bain Capital Private Equity, LP, 200 Clarendon Street, Boston, MA 02116.

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#### DESCRIPTION OF CAPITAL STOCK
The following is a description of the material terms of, and is qualified in its entirety by, our amended and restated certificate of incorporation and amended and restated bylaws, which are filed as exhibits to the registration statement of which this prospectus is a part. For a complete description of our capital stock, you should refer to our amended and restated certificate of incorporation, amended and restated bylaws, and the applicable provisions of Delaware law. In this section, "we," "us," "our," "the Company," and "our Company" refer to Waystar Holding Corp. and not to any of its subsidiaries and "Institutional Investors" refers to EQT, CPPIB, and Bain, in each case, so long as they own shares of common stock of our Company.

Our purpose is to engage in any lawful act or activity for which corporations may be organized under the DGCL. Our authorized capital stock consists of 2,500,000,000 shares of our common stock, $0.01 par value per share; and 100,000,000 shares of preferred stock, par value $0.01 per share. No shares of preferred stock will be issued or outstanding immediately after the offering contemplated by this prospectus. Unless our board of directors determines otherwise, we will issue all shares of our capital stock in uncertificated form.

#### Common Stock

#### Voting Rights
Each holder of our common stock is entitled to one vote per share on all matters submitted to a vote of the stockholders. The holders of our common stock do not have cumulative voting rights in the election of directors.

#### Dividend Rights
The holders of our common stock are entitled to receive dividends as may be declared from time to time by our board of directors out of legally available funds.

#### Liquidation
In the event of our liquidation, dissolution, or winding up and after payment in full of all amounts required to be paid to creditors and to the holders of preferred stock having liquidation preferences, if any, holders of our common stock will be entitled to share ratably in the net assets legally available for distribution to stockholders.

#### Rights and Preferences
Holders of our common stock have no preemptive, conversion, or subscription rights, and there are no redemption or sinking fund provisions applicable to our common stock.

#### Fully Paid and Non-assessable
All shares of our common stock that will be outstanding at the time of the completion of an offering will be fully paid and non-assessable.

The rights, powers, preferences, and privileges of holders of our common stock will be subject to those of the holders of any shares of our preferred stock we may authorize and issue in the future.

#### Preferred Stock
Our amended and restated certificate of incorporation authorizes our board of directors to establish one or more series of preferred stock (including convertible preferred stock). Unless required by law or by the applicable stock exchange, the authorized shares of preferred stock will be available for issuance without further action by you. Our board of directors may determine, with respect to any series of preferred stock, the terms and rights of that series, including:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the designation of the series;

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the number of shares of the series, which our board of directors may, except where otherwise provided in the preferred stock designation, increase (but not above the total number of authorized shares of the class) or decrease (but not below the number of shares then outstanding);

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • whether dividends, if any, will be cumulative or non-cumulative and the dividend rate of the series;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the dates at which dividends, if any, will be payable;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the redemption rights and price or prices, if any, for shares of the series;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the terms and amounts of any sinking fund provided for the purchase or redemption of shares of the series;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the amounts payable on shares of the series in the event of any voluntary or involuntary liquidation, dissolution or winding-up of the affairs of the Company;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • whether the shares of the series will be convertible into shares of any other class or series, or any other security, of the Company or any other corporation and, if so, the specification of the other class or series or other security, the conversion price or prices or rate or rates, any rate adjustments, the date or dates as of which the shares will be convertible and all other terms and conditions upon which the conversion may be made;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • restrictions on the issuance of shares of the same series or of any other class or series of our capital stock; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the voting rights, if any, of the holders of the series.

We may issue a series of preferred stock that could, depending on the terms of the series, impede or discourage an acquisition attempt or other transaction that some, or a majority, of the holders of our common stock might believe to be in their best interests or in which the holders of our common stock might receive a premium for their common stock over the market price of the common stock. In addition, the issuance of preferred stock may adversely affect the holders of our common stock by restricting dividends on the common stock, diluting the voting power of the common stock or subordinating the liquidation rights of the common stock. In addition, the issuance of preferred stock could have the effect of delaying, deferring, or preventing a change of control, or other corporate action. As a result of these or other factors, the issuance of preferred stock may have an adverse impact on the market price of our common stock.

#### Dividends
The DGCL permits a corporation to declare and pay dividends out of "surplus" or, if there is no "surplus," out of its net profits for the fiscal year in which the dividend is declared and/or the preceding fiscal year. "Surplus" is defined as the excess of the net assets of the corporation over the amount determined to be the capital of the corporation by our board of directors. The capital of the corporation is typically calculated to be (and cannot be less than) the aggregate par value of all issued shares of capital stock. Net assets equal the fair value of the total assets minus total liabilities. The DGCL also provides that dividends may not be paid out of net profits if, after the payment of the dividend, capital is less than the capital represented by the outstanding stock of all classes having a preference upon the distribution of assets.

Declaration and payment of any dividend will be subject to the discretion of our board of directors. The time and amount of dividends will be dependent upon our financial condition, operations, cash requirements, and availability, debt repayment obligations, capital expenditure needs, and restrictions in our debt instruments, industry trends, the provisions of Delaware law affecting the payment of dividends to stockholders and any other factors our board of directors may consider relevant.

We do not expect to declare or pay any dividends on our common stock in the foreseeable future. In addition, our ability to pay dividends on our common stock is limited by the covenants of our existing credit agreements and may be further restricted by the terms of any future debt or preferred securities. See Part II, Item 7, "Management's Discussion and Analysis of Financial Condition and Results of Operations — Liquidity and Capital Resources — Indebtedness" of our Annual Report on Form 10-K and Part I, Item 2, "Management's Discussion and Analysis of Financial Condition and Results of Operations — Liquidity and Capital Resources" and "— Indebtedness" of our Quarterly Report on Form 10-Q for the quarterly period ended March 31, 2025.

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#### Anti-takeover Effects of Our Amended and Restated Certificate of Incorporation and Amended and Restated Bylaws, and Certain Provisions of Delaware Law
Our amended and restated certificate of incorporation, amended and restated bylaws, and the DGCL, which are summarized in the following paragraphs, contain provisions that are intended to enhance the likelihood of continuity and stability in the composition of our board of directors. These provisions are intended to avoid costly takeover battles, reduce our vulnerability to a hostile change of control, and enhance the ability of our board of directors to maximize stockholder value in connection with any unsolicited offer to acquire us. However, these provisions may have an anti-takeover effect and may delay, deter, or prevent a merger or acquisition of the Company by means of a tender offer, a proxy contest, or other takeover attempt that a stockholder might consider is in its best interest, including those attempts that might result in a premium over the prevailing market price for the shares of common stock held by stockholders.

#### Authorized but Unissued Capital Stock
Delaware law does not require stockholder approval for any issuance of authorized shares. However, the listing requirements of Nasdaq, which apply so long as our common stock remains listed on Nasdaq, require stockholder approval of certain issuances equal to or exceeding 20% of the then-outstanding voting power or then-outstanding number of shares of common stock. These additional shares may be used for a variety of corporate purposes, including future public offerings to raise additional capital or to facilitate acquisitions.

Our board of directors may issue shares of preferred stock on terms calculated to discourage, delay, or prevent a change of control of the Company or the removal of our management. Moreover, our authorized but unissued shares of preferred stock are available for future issuances without stockholder approval and could be utilized for a variety of corporate purposes, including future offerings to raise additional capital, acquisitions, or employee benefit plans.

One of the effects of the existence of unissued and unreserved common stock or preferred stock may be to enable our board of directors to issue shares to persons friendly to current management, which issuance could render more difficult or discourage an attempt to obtain control of the Company by means of a merger, tender offer, proxy contest, or otherwise, and thereby protect the continuity of our management and possibly deprive our stockholders of opportunities to sell their shares of common stock at prices higher than prevailing market prices.

#### Director Nomination Rights
Our amended and restated certificate of incorporation, as amended as of June 4, 2025, provides that our board of directors will consist of the number of directors as determined from time to time exclusively by resolution adopted by the board of directors (which shall include the consent of each of the director nominees as described below for so long as EQT, CPPIB, and Bain, as applicable, have the right to nominate such directors), and not less than the number of directors as is required to allow for the election of each director nominee as described below. EQT will have the right to nominate to our board of directors (i) two nominees for so long as EQT beneficially owns 25% or greater of our then-outstanding common stock, and (ii) one nominee for so long as EQT beneficially owns 5% or greater, but less than 25% of our then-outstanding common stock. As of June 30, 2025, EQT beneficially owned 18.7% of our outstanding shares of common stock. CPPIB will have the right to nominate to our board of directors one nominee for so long as CPPIB beneficially owns 5% or greater of our then-outstanding common stock. Bain will have the right to nominate to our board of directors one nominee for so long as Bain beneficially owns 5% or greater of our then-outstanding common stock. In addition, we will cause the nomination of five independent director nominees as well as the nomination of the person who, as of the date of nomination, is then-serving as our Chief Executive Officer. As of the date of this prospectus, each of EQT, CPPIB, and Bain has the right to one director nominee pursuant to the foregoing director nomination rights.

Further, for so long as EQT, CPPIB, and Bain collectively beneficially own 5% or greater of our then- outstanding common stock, (i) the Bain director nominee will be appointed to serve on the Audit, Compliance, & Risk Committee, (ii) the CPPIB director nominee and one EQT director nominee will be appointed to serve on the Talent & Compensation Committee, and (iii) the CPPIB director nominee and one

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EQT director nominee will be appointed to serve on the Nominating and Corporate Governance Committee, subject to certain exceptions.

#### Classified Board of Directors
Our amended and restated certificate of incorporation provides that, subject to the right of holders of any series of preferred stock, our board of directors will be divided into three classes of directors, with the classes to be as nearly equal in number as possible, and with the directors serving three-year terms, with only one class of directors being elected at each annual meeting of stockholders. At the second annual meeting of stockholders after the date on which the Institutional Investors collectively own less than 15% in voting power of the then-outstanding power of the then-outstanding shares of stock of our Company entitled to vote generally in the election of directors (the "Triggering Annual Meeting"), and each annual meeting of stockholders thereafter, all directors shall be elected to hold office for a one-year term expiring at the next annual meeting of stockholders. Pursuant to such procedures, effective as of the Triggering Annual Meeting, our board of directors will no longer be classified under Section 141(d) of the DGCL and directors shall no longer be divided into three classes. As a result, prior to the Triggering Annual Meeting, approximately one-third of our board of directors will be elected each year. The classification of directors prior to the Triggering Annual Meeting has the effect of making it more difficult for stockholders to change the composition of our board of directors. Our amended and restated certificate of incorporation and amended and restated bylaws provide that, subject to any rights of holders of preferred stock to elect additional directors under specified circumstances, the number of directors will be fixed from time to time exclusively pursuant to a resolution adopted by our board of directors; however, if at any time the Institutional Investors collectively own at least 40% in voting power of the then-outstanding shares of stock of our Company entitled to vote generally in the election of directors, the stockholders may also fix the number of directors.

#### Business Combinations
We have opted out of Section 203 of the DGCL; however, our amended and restated certificate of incorporation contains similar provisions providing that we may not engage in certain "business combinations" with any "interested stockholder" for a three-year period following the time that the stockholder became an interested stockholder, unless:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • prior to such time, our board of directors approved either the business combination or the transaction that resulted in the stockholder becoming an interested stockholder;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • upon consummation of the transaction which resulted in the stockholder becoming an interested stockholder, the interested stockholder owned at least 85% of our voting stock outstanding at the time the transaction commenced, excluding certain shares;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • at or subsequent to that time, the business combination is approved by our board of directors and by the affirmative vote of holders of at least 66-2/3% of our outstanding voting stock that is not owned by the interested stockholder; or

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the stockholder became an interested stockholder inadvertently and (i) as soon as practicable divested itself of sufficient ownership to cease to be an interested stockholder and (ii) had not been an interested stockholder but for the inadvertent acquisition of ownership within three years of the business combination.

Generally, a "business combination" includes a merger, asset, or stock sale or other transaction resulting in a financial benefit to the interested stockholder. Subject to certain exceptions, an "interested stockholder" is a person who, together with that person's affiliates and associates, owns, or within the previous three years owned, 15% or more of our outstanding voting stock. For purposes of this section only, "voting stock" has the meaning given to it in Section 203 of the DGCL.

Under certain circumstances, these provisions make it more difficult for a person who would be an "interested stockholder" to effect various business combinations with our company for a three-year period. These provisions may encourage companies interested in acquiring our Company to negotiate in advance with our board of directors because the stockholder approval requirement would be avoided if our board of directors approves either the business combination or the transaction which results in the stockholder

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becoming an interested stockholder. These provisions also may have the effect of preventing changes in our board of directors and may make it more difficult to accomplish transactions that stockholders may otherwise deem to be in their best interests.

Our amended and restated certificate of incorporation provides that each of the Institutional Investors, and any of their respective direct or indirect transferees and any group as to which such persons or entities are a party, does not constitute an "interested stockholder" for purposes of these provisions.

#### Removal of Directors; Vacancies
Under the DGCL, unless otherwise provided in our amended and restated certificate of incorporation, directors serving on a classified board may be removed by the stockholders only for cause. Our amended and restated certificate of incorporation provides that, other than directors elected by holders of our preferred stock, if any, directors may be removed with or without cause upon the affirmative vote of a majority in voting power of all outstanding shares of stock entitled to vote thereon, voting together as a single class; provided, however, at any time commencing on the day on which the Institutional Investors collectively beneficially own less than 40% in voting power of the then-outstanding shares of stock of our company entitled to vote generally in the election of directors and ending immediately following the final adjournment of the Triggering Annual Meeting (such period, the "Protective Period"), directors may only be removed for cause, and only by the affirmative vote of holders of at least 66-2/3% in voting power of all the then-outstanding shares of stock of our company entitled to vote thereon, voting together as a single class. In addition, our amended and restated certificate of incorporation will also provide that, subject to the rights granted to one or more series of preferred stock then outstanding or the rights granted pursuant to the Stockholders Agreement, any newly created directorship on our board of directors that results from an increase in the number of directors and any vacancies on our board of directors will be filled only by the affirmative vote of a majority of the remaining directors, even if less than a quorum, or by a sole remaining director or by the stockholders; provided, however, at any time when the Institutional Investors collectively beneficially own less than 40% in voting power of the then-outstanding shares of stock of our company entitled to vote generally in the election of directors, any newly created directorship on our board of directors that results from an increase in the number of directors and any vacancy occurring in our board of directors may only be filled by a majority of the directors then in office, although less than a quorum, or by a sole remaining director (and not by the stockholders). Our amended and restated certificate of incorporation provides that our board of directors may increase the number of directors by the affirmative vote of a majority of the directors or, at any time when the Institutional Investors collectively beneficially own at least 40% of the voting power of the then-outstanding shares of stock of our Company entitled to vote generally in the election of directors, of the stockholders.

Notwithstanding the foregoing, EQT, CPPIB, or Bain, as applicable, shall have the exclusive right to remove their respective nominees from our board of directors, with or without cause. For so long as EQT, CPPIB, or Bain have the right to nominate their respective directors, the shares of common stock held by EQT, CPPIB, or Bain, as applicable, shall be the only shares entitled to vote on the removal without cause of any of their respective nominees, and the shares of common stock owned by any holders as of the record date for determining stockholders entitled to vote thereon shall have no voting rights on such matter.

#### No Cumulative Voting
Under Delaware law, the right to vote cumulatively does not exist unless the certificate of incorporation specifically authorizes cumulative voting. Our amended and restated certificate of incorporation does not authorize cumulative voting. Therefore, stockholders holding a majority in voting power of the then- outstanding shares of our stock entitled to vote generally in the election of directors are able to elect all of our directors.

#### Special Stockholder Meetings
Our amended and restated certificate of incorporation provides that special meetings of our stockholders may be called at any time only by or at the direction of our board of directors or the chairman of our board of directors; provided, however, at any time when the Institutional Investors beneficially own, in the aggregate, at least 40% in voting power of the then-outstanding shares of stock of our Company entitled to

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vote generally in the election of directors, special meetings of our stockholders may be called at any time by or at the direction of our board of directors or the chairman of our board of directors and shall be called by the secretary of our company at the request of at least two of the Institutional Investors. Our amended and restated bylaws prohibit the conduct of any business at a special meeting other than as specified in the notice for such meeting. These provisions may have the effect of deferring, delaying, or discouraging hostile takeovers, or changes in control or management of the Company.

#### Requirements for Advance Notification of Director Nominations and Stockholder Proposals
Our amended and restated bylaws establish advance notice procedures with respect to stockholder proposals and the nomination of candidates for election as directors, other than nominations made as provided in our amended and restated certificate of incorporation, the Stockholders Agreement or by or at the direction of our board of directors or a committee of our board of directors. In order for any matter to be "properly brought" before a meeting, a stockholder will have to comply with advance notice requirements and provide us with certain information. Generally, to be timely, a stockholder's notice must be received at our principal executive offices not less than 90 days nor more than 120 days prior to the first anniversary date of the immediately preceding annual meeting of stockholders. Our amended and restated bylaws also specify requirements as to the form and content of a stockholder's notice. Our amended and restated bylaws allow the chairman of the meeting at a meeting of the stockholders to adopt rules and regulations for the conduct of meetings which may have the effect of precluding the conduct of certain business at a meeting if the rules and regulations are not followed. These notice requirements will not apply to the Institutional Investors and their affiliates for as long as the Stockholders Agreement remains in effect. These provisions may also deter, delay, or discourage a potential acquirer from conducting a solicitation of proxies to elect the acquirer's own slate of directors or otherwise attempting to influence or obtain control of the Company.

#### Stockholder Action by Written Consent
Pursuant to Section 228 of the DGCL, any action required to be taken at any annual or special meeting of the stockholders may be taken without a meeting, without prior notice and without a vote if a consent or consents in writing, setting forth the action so taken, is signed by the holders of outstanding stock having not less than the minimum number of votes that would be necessary to authorize or take such action at a meeting at which all shares of our stock entitled to vote thereon were present and voted, unless our amended and restated certificate of incorporation provides otherwise. Our amended and restated certificate of incorporation precludes stockholder action by written consent at any time when the Institutional Investors collectively beneficially own less than 40% in voting power of the then-outstanding shares of stock of our Company entitled to vote generally in the election of directors, other than certain rights that holders of our preferred stock may have to act by consent.

#### Supermajority Provisions
Our amended and restated certificate of incorporation and our amended and restated bylaws provide that our board of directors is expressly authorized to make, alter, amend, change, add to, rescind, or repeal, in whole or in part, our amended and restated bylaws without a stockholder vote in any matter not inconsistent with Delaware law or our amended and restated certificate of incorporation. Any amendment, alteration, rescission, or repeal, of our amended and restated bylaws by our stockholders requires the affirmative vote of a majority in voting power of the outstanding shares of our stock present in person or represented by proxy at the meeting of stockholders and entitled to vote on such amendment, alteration, change, addition, rescission, change, addition, or repeal, except that during the Protective Period, any amendment, alteration, rescission, change, addition, or repeal of our amended and restated bylaws by our stockholders will require the affirmative vote of the holders of at least 66-2/3% in voting power of all the then- outstanding shares of stock of our Company entitled to vote thereon, voting together as a single class.

The DGCL provides generally that the affirmative vote of a majority of the outstanding shares entitled to vote thereon, voting together as a single class, is required to amend a corporation's certificate of incorporation, unless the certificate of incorporation requires a greater percentage.

Our amended and restated certificate of incorporation provides that during the Protective Period, the following provisions in our amended and restated certificate of incorporation may be amended, altered,

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repealed, or rescinded only by the affirmative vote of the holders of at least 66-2/3% in voting power of all the then-outstanding shares of stock of our company entitled to vote thereon, voting together as a single class:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the provision requiring a 66-2/3% supermajority vote for stockholders to amend our amended and restated bylaws;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the provisions providing for a classified board of directors (the election and term of our directors);

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the provisions regarding resignation and removal of directors;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the provisions regarding competition and corporate opportunities;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the provisions regarding entering into business combinations with interested stockholders;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the provisions regarding stockholder action by written consent;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the provisions regarding calling annual or special meetings of stockholders;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the provisions regarding filling vacancies on our board of directors and newly created directorships;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the provisions eliminating monetary damages for breaches of fiduciary duty by a director or officer; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the amendment provision requiring that the above provisions be amended only with a 66-2/3% supermajority vote.

The combination of the classification of our board of directors, the lack of cumulative voting and the supermajority voting requirements will make it more difficult for our existing stockholders to replace our board of directors as well as for another party to obtain control of us by replacing our board of directors. Because our board of directors has the power to retain and discharge our officers, these provisions could also make it more difficult for existing stockholders or another party to effect a change in management.

These provisions may have the effect of deterring hostile takeovers, delaying, or preventing changes in control of our management or the Company, such as a merger, reorganization or tender offer. These provisions are intended to enhance the likelihood of continued stability in the composition of our board of directors and its policies and to discourage certain types of transactions that may involve an actual or threatened acquisition of the Company. These provisions are designed to reduce our vulnerability to an unsolicited acquisition proposal. The provisions are also intended to discourage certain tactics that may be used in proxy fights. However, such provisions could have the effect of discouraging others from making tender offers for our shares and, as a consequence, they also may inhibit fluctuations in the market price of our shares that could result from actual or rumored takeover attempts. Such provisions may also have the effect of preventing changes in management.

#### Dissenters' Rights of Appraisal and Payment
Under the DGCL, with certain exceptions, our stockholders will have appraisal rights in connection with a merger or consolidation of us. Pursuant to the DGCL, stockholders who properly request and perfect appraisal rights in connection with such merger or consolidation will have the right to receive payment of the fair value of their shares as determined by the Delaware Court of Chancery.

#### Stockholders' Derivative Actions
Under the DGCL, any of our stockholders may bring an action in our name to procure a judgment in our favor, also known as a derivative action, provided that the stockholder bringing the action is a holder of our shares at the time of the transaction to which the action relates or such stockholder's stock thereafter devolved by operation of law.

#### Exclusive Forum
Our amended and restated certificate of incorporation provides that unless we consent in writing to the selection of an alternative forum, the Court of Chancery of the State of Delaware (or if such court does not have subject matter jurisdiction another state or the federal court (as appropriate) located within the State

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#### Conflicts of Interest
Delaware law permits corporations to adopt provisions renouncing any interest or expectancy in certain opportunities that are presented to the corporation or its officers, directors, or stockholders. Our amended and restated certificate of incorporation, to the maximum extent permitted from time to time by Delaware law, renounces any interest or expectancy that we have in, or right to be offered an opportunity to participate in, specified business opportunities that are from time to time presented to our officers, directors, or stockholders or their respective affiliates, other than those officers, directors, stockholders, or affiliates who are our or our subsidiaries' employees. Our amended and restated certificate of incorporation provides that, to the fullest extent permitted by law, none of the Institutional Investors or any director who is not employed by us (including any non-employee director who serves as one of our officers in both his or her director and officer capacities) or his or her affiliates will have any duty to refrain from (1) engaging in a corporate opportunity in the same or similar business activities or lines of business in which we or our affiliates now engage or propose to engage or (2) otherwise competing with us or our affiliates. In addition, to the fullest extent permitted by law, in the event that any of the Institutional Investors or any non-employee director acquires knowledge of a potential transaction or other business opportunity which may be a corporate opportunity for itself or himself or its or his affiliates or for us or our affiliates, such person will have no duty to communicate or offer such transaction or business opportunity to us or any of our affiliates and they may take any such opportunity for themselves or offer it to another person or entity. Our amended and restated certificate of incorporation does not renounce our interest in any business opportunity that is expressly offered to a non-employee director solely in his or her capacity as a director or officer of the Company. To the fullest extent permitted by law, no business opportunity will be deemed to be a potential corporate opportunity for us unless we would be permitted to undertake the opportunity under our amended and restated certificate of incorporation, we have sufficient financial resources to undertake the opportunity and the opportunity would be in line with our business.

#### Limitations on Liability and Indemnification of Officers and Directors
The DGCL authorizes corporations to limit or eliminate the personal liability of directors and certain officers to corporations and their stockholders for monetary damages for breaches of directors' fiduciary

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duties, subject to certain exceptions. Our amended and restated certificate of incorporation includes a provision that eliminates the personal liability of directors and officers for monetary damages for any breach of fiduciary duty as a director or officer, except to the extent such exemption from liability or limitation thereof is not permitted under the DGCL. The effect of these provisions is to eliminate the rights of us and our stockholders, through stockholders' derivative suits on our behalf, to recover monetary damages from a director for breach of fiduciary duty as a director, including breaches resulting from grossly negligent behavior. This provision does not limit or eliminate the liability of any officer in any action by or in the right of the Company, including any derivative claims. However, exculpation will not apply to any director if the director has breached the duty of loyalty to the corporation and its stockholders, acted in bad faith, knowingly or intentionally violated the law, authorized illegal dividends or redemptions, or derived an improper benefit from his or her actions as a director.

Our amended and restated bylaws provide that we must generally indemnify, and advance expenses to, our directors and officers to the fullest extent authorized by the DGCL. We also are expressly authorized to carry directors' and officers' liability insurance providing indemnification for our directors, officers, and certain employees for some liabilities. We also have entered into indemnification agreements with our directors, which agreements require us to indemnify these individuals to the fullest extent permitted under Delaware law against liabilities that may arise by reason of their service to us, and to advance expenses incurred as a result of any proceeding against them as to which they could be indemnified. We believe that these indemnification and advancement provisions and insurance are useful to attract and retain qualified directors and officers.

The limitation of liability, indemnification, and advancement provisions in our amended and restated certificate of incorporation and amended and restated bylaws may discourage stockholders from bringing a lawsuit against directors or officers for breach of their fiduciary duty. These provisions also may have the effect of reducing the likelihood of derivative litigation against directors and officers, even though such an action, if successful, might otherwise benefit us and our stockholders. In addition, your investment may be adversely affected to the extent we pay the costs of settlement and damage awards against directors and officers pursuant to these indemnification provisions.

There is currently no pending material litigation or proceeding involving any of our directors, officers, or employees for which indemnification is sought.

#### Transfer Agent and Registrar
The transfer agent and registrar for our common stock is Broadridge Corporate Issuer Solutions, LLC.

#### Listing
Our common stock is listed on Nasdaq under the symbol "WAY."

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#### CERTAIN UNITED STATES FEDERAL INCOME TAX CONSEQUENCES TO NON-U.S. HOLDERS
The following is a summary of certain United States federal income tax consequences of the ownership and disposition of our common stock. This summary deals only with common stock that is held as a capital asset by a non-U.S. holder (as defined below).

A "non-U.S. holder" means a beneficial owner of our common stock (other than an entity or arrangement treated as a partnership for United States federal income tax purposes) that is not, for United States federal income tax purposes, any of the following:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • an individual citizen or resident of the United States;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • a corporation (or any other entity treated as a corporation for United States federal income tax purposes) created or organized in or under the laws of the United States, any state thereof or the District of Columbia;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • an estate the income of which is subject to United States federal income taxation regardless of its source; or

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • a trust if it (1) is subject to the primary supervision of a court within the United States and one or more United States persons have the authority to control all substantial decisions of the trust or (2) has a valid election in effect under applicable United States Treasury regulations to be treated as a United States person.

This summary is based upon provisions of the Internal Revenue Code of 1986, as amended (the "Code"), United States Treasury regulations, rulings and judicial decisions as of the date hereof. Those authorities may be changed, perhaps retroactively, so as to result in United States federal income tax consequences different from those summarized below. This summary does not address all aspects of United States federal income taxes and does not deal with the Medicare contribution tax on net investment income, the alternative minimum tax, United States federal estate or gift taxes, or any foreign, state, local, or other tax considerations that may be relevant to non-U.S. holders in light of their particular circumstances. In addition, it does not represent a detailed description of the United States federal income tax consequences applicable to you if you are subject to special treatment under the United States federal income tax laws (including if you are a United States expatriate, foreign pension fund, "controlled foreign corporation," "passive foreign investment company," tax-exempt or governmental organization, brokers, dealer or trader in securities, bank, insurance company, or a partnership or other pass-through entity for United States federal income tax purposes (and investors therein)). We cannot assure you that a change in law will not alter significantly the tax considerations that we describe in this summary.

If a partnership (or other entity or arrangement treated as a partnership for United States federal income tax purposes) holds our common stock, the tax treatment of a partner will generally depend upon the status of the partner and the activities of the partnership. If you are a partner of a partnership holding our common stock, you should consult your tax advisors.

If you are considering the purchase of our common stock, you should consult your own tax advisors concerning the particular United States federal income tax consequences to you of the ownership and disposition of our common stock, as well as the consequences to you arising under other United States federal tax laws and the laws of any other taxing jurisdiction.

#### Dividends
In the event that we make a distribution of cash or other property (other than certain pro rata distributions of our stock) in respect of our common stock, the distribution generally will be treated as a dividend for United States federal income tax purposes to the extent it is paid from our current or accumulated earnings and profits, as determined under United States federal income tax principles. Any portion of a distribution that exceeds our current and accumulated earnings and profits generally will be treated first as a tax-free return of capital, causing a reduction in the adjusted tax basis of a non-U.S. holder's common stock, and to the extent the amount of the distribution exceeds a non-U.S. holder's adjusted tax basis in our

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common stock, the excess will be treated as gain from the disposition of our common stock (the tax treatment of which is discussed below under "— Gain on Disposition of Common Stock").

Dividends paid to a non-U.S. holder generally will be subject to withholding of United States federal income tax at a 30% rate or such lower rate as may be specified by an applicable income tax treaty. However, dividends that are effectively connected with the conduct of a trade or business by the non-U.S. holder within the United States (and, if required by an applicable income tax treaty, are attributable to a United States permanent establishment) are not subject to the withholding tax, provided certain certification and disclosure requirements (including by providing a valid Internal Revenue Service ("IRS") Form W-8ECI) are satisfied. Instead, such dividends are subject to United States federal income tax on a net income basis in the same manner as if the non-U.S. holder were a United States person as defined under the Code. Any such effectively connected dividends received by a foreign corporation may be subject to an additional "branch profits tax" at a 30% rate or such lower rate as may be specified by an applicable income tax treaty.

A non-U.S. holder who wishes to claim the benefit of an applicable income tax treaty rate and avoid backup withholding, as discussed below, for dividends will be required (a) to provide the applicable withholding agent with a properly executed IRS Form W-BEN or Form W-8BEN-E (or other applicable form) certifying under penalty of perjury that such holder is not a United States person as defined under the Code and is eligible for treaty benefits or (b) if our common stock is held through certain foreign intermediaries, to satisfy the relevant certification requirements of applicable United States Treasury regulations. Special certification and other requirements apply to certain non-U.S. holders that are pass-through entities rather than corporations or individuals.

A non-U.S. holder eligible for a reduced rate of United States federal withholding tax pursuant to an applicable income tax treaty may obtain a refund of any excess amounts withheld by timely filing an appropriate claim for refund with the IRS.

#### Gain on Disposition of Common Stock
Subject to the discussions of backup withholding and FATCA (as defined below) below, any gain realized by a non-U.S. holder on the sale or other disposition of our common stock generally will not be subject to United States federal income or withholding tax unless:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the gain is effectively connected with a trade or business of the non-U.S. holder in the United States (and, if required by an applicable income tax treaty, is attributable to a United States permanent establishment of the non-U.S. holder);

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the non-U.S. holder is an individual who is present in the United States for 183 days or more in the taxable year of that disposition, and certain other conditions are met; or

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • we are or have been a "United States real property holding corporation" for United States federal income tax purposes and certain other conditions are met.

A non-U.S. holder described in the first bullet point immediately above will be subject to tax on the gain derived from the sale or other disposition in the same manner as if the non-U.S. holder were a United States person as defined under the Code. In addition, if any non-U.S. holder described in the first bullet point immediately above is a foreign corporation, the gain realized by such non-U.S. holder may be subject to an additional "branch profits tax" at a 30% rate or such lower rate as may be specified by an applicable income tax treaty. An individual non-U.S. holder described in the second bullet point immediately above will be subject to a 30% (or such lower rate as may be specified by an applicable income tax treaty) tax on the gain derived from the sale or other disposition, which gain may be offset by United States source capital losses even though the individual is not considered a resident of the United States.

Generally, a corporation is a "United States real property holding corporation" if the fair market value of its United States real property interests equals or exceeds 50% of the sum of the fair market value of its worldwide real property interests and its other assets used or held for use in a trade or business (all as determined for United States federal income tax purposes). We believe we are not and do not anticipate becoming a "United States real property holding corporation" for United States federal income tax purposes.

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#### Information Reporting and Backup Withholding
Distributions paid to a non-U.S. holder and the amount of any tax withheld with respect to such distributions generally will be reported to the IRS. Copies of the information returns reporting such distributions and any withholding may also be made available to the tax authorities in the country in which the non-U.S. holder resides under the provisions of an applicable income tax treaty.

A non-U.S. holder will not be subject to backup withholding on dividends received if such holder certifies under penalty of perjury that it is a non-U.S. holder (and the payor does not have actual knowledge or reason to know that such holder is a United States person as defined under the Code), or such holder otherwise establishes an exemption.

Information reporting and, depending on the circumstances, backup withholding will apply to the proceeds of a sale or other disposition of our common stock made within the United States or conducted through certain United States-related financial intermediaries, unless the beneficial owner certifies under penalty of perjury that it is a non-U.S. holder (and the payor does not have actual knowledge or reason to know that the beneficial owner is a United States person as defined under the Code), or such owner otherwise establishes an exemption.

Backup withholding is not an additional tax and any amounts withheld under the backup withholding rules will be allowed as a refund or a credit against a non-U.S. holder's United States federal income tax liability, provided the required information is timely furnished to the IRS.

#### Additional Withholding Requirements
Under Sections 1471 through 1474 of the Code (such Sections commonly referred to as "FATCA"), a 30% United States federal withholding tax may apply to any dividends paid on our common stock to (i) a "foreign financial institution" (as specifically defined in the Code and whether such foreign financial institution is the beneficial owner or an intermediary) which does not provide sufficient documentation, typically on IRS Form W-8BEN-E, evidencing either (x) an exemption from FATCA, or (y) its compliance (or deemed compliance) with FATCA (which may alternatively be in the form of compliance with an intergovernmental agreement with the United States) in a manner which avoids withholding, or (ii) a "non-financial foreign entity" (as specifically defined in the Code and whether such non-financial foreign entity is the beneficial owner or an intermediary) which does not provide sufficient documentation, typically on IRS Form W-8BEN-E, evidencing either (x) an exemption from FATCA, or (y) adequate information regarding certain substantial United States beneficial owners of such entity (if any). If a dividend payment is both subject to withholding under FATCA and subject to the withholding tax discussed above under "— Dividends," an applicable withholding agent may credit the withholding under FATCA against, and therefore reduce, such other withholding tax. FATCA withholding may also apply to payments of gross proceeds of dispositions of our common stock, although under proposed regulations (the preamble to which specifies that taxpayers are permitted to rely on them pending finalization), no withholding will apply on payments of gross proceeds. You should consult your own tax advisors regarding these requirements and whether they may be relevant to your ownership and disposition of our common stock.

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#### PLAN OF DISTRIBUTION
The selling stockholders, and their pledgees, donees, transferees or other successors in interest, may from time to time offer and sell, separately or together, shares of common stock covered by this prospectus. Registration of the shares of common stock covered by this prospectus does not mean, however, that those shares of common stock necessarily will be offered or sold.

The shares of common stock covered by this prospectus may be sold in one or more transactions from time to time, at market prices prevailing at the time of sale, at prices related to market prices, at a fixed price or prices subject to change or at negotiated prices, by a variety of methods including the following:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • on Nasdaq or any other national securities exchange or U.S. inter-dealer system of a registered national securities association (including through at-the-market offerings);

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • in the over-the-counter market;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • in privately negotiated transactions;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • to or through broker-dealers, who may act as agents or principals;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • to or through one or more underwriters on a firm commitment or best-efforts basis;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • in a block trade in which a broker-dealer will attempt to sell a block of shares of common stock as agent but may position and resell a portion of the block as principal to facilitate the transaction;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • through put or call option transactions relating to the shares of common stock;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • directly to one or more purchasers;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • to or through agents; or

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • in any combination of the above.

In effecting sales, brokers, or dealers engaged by us and/or the selling stockholders may arrange for other brokers or dealers to participate. Broker-dealer transactions may include:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • purchases of the shares of common stock by a broker-dealer as principal and resales of the shares of common stock by the broker-dealer for its account pursuant to this prospectus;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • ordinary brokerage transactions; or

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • transactions in which the broker-dealer solicits purchasers on a best efforts basis.

The selling stockholders have not entered into any agreements, understandings, or arrangements with any underwriters or broker-dealers regarding the sale of the common stock covered by this prospectus. At any time a particular offer of the shares of common stock covered by this prospectus is made, a revised prospectus or prospectus supplement, if required, will set forth the aggregate amount of shares of common stock covered by this prospectus being offered and the terms of the offering, including the name or names of any underwriters, dealers, brokers, or agents. In addition, to the extent required, any discounts, commissions, concessions, and other items constituting underwriters' or agents' compensation, as well as any discounts, commissions, or concessions allowed or reallowed or paid to dealers, will be set forth in such prospectus supplement. To the extent required, any such prospectus supplement, and, if necessary, a post-effective amendment to the registration statement of which this prospectus is a part, will be filed with the SEC to reflect the disclosure of additional information with respect to the distribution of the shares of common stock covered by this prospectus.

To the extent required, the applicable prospectus supplement will set forth whether or not underwriters may over-allot or effect transactions that stabilize, maintain, or otherwise affect the market price of the common stock at levels above those that might otherwise prevail in the open market, including, for example, by entering stabilizing bids, effecting syndicate covering transactions or imposing penalty bids.

If the selling stockholders utilize a dealer in the sale of the securities being offered pursuant to this prospectus, the selling stockholders will sell the securities to the dealer, as principal. The dealer may then resell the securities to the public at varying prices to be determined by the dealer at the time of resale.

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The selling stockholders may also authorize agents or underwriters to solicit offers by certain types of institutional investors to purchase securities at the public offering price set forth in the revised prospectus or prospectus supplement pursuant to delayed delivery contracts providing for payment and delivery on a specified date in the future. The conditions to these contracts and the commission that the selling stockholders must pay for solicitation of these contracts will be described in a revised prospectus or prospectus supplement, to the extent such revised prospectus or prospectus supplement is required.

In connection with the sale of the shares of common stock covered by this prospectus through underwriters, underwriters may receive compensation in the form of underwriting discounts or commissions and may also receive commissions from purchasers of shares of common stock for whom they may act as agent. Underwriters may sell to or through dealers, and such dealers may receive compensation in the form of discounts, concessions, or commissions from the underwriters and/or commissions from the purchasers for whom they may act as agent.

Any underwriters, broker-dealers, or agents participating in the distribution of the shares of common stock covered by this prospectus may be deemed to be "underwriters" within the meaning of the Securities Act, and any commissions received by any of those underwriters, broker-dealers, or agents may be deemed to be underwriting commissions under the Securities Act.

We and the selling stockholders may agree to indemnify underwriters, broker-dealers, or agents against certain liabilities, including liabilities under the Securities Act, and may also agree to contribute to payments which the underwriters, broker-dealers, or agents may be required to make.

Certain of the underwriters, broker-dealers, or agents who may become involved in the sale of the shares of common stock may engage in transactions with and perform other services for us in the ordinary course of their business for which they receive customary compensation.

Some of the shares of common stock covered by this prospectus may be sold by selling stockholders in private transactions or under Rule 144 under the Securities Act rather than pursuant to this prospectus.

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#### LEGAL MATTERS
The validity of the shares of common stock will be passed upon for us by Simpson Thacher & Bartlett LLP. Additional legal matters may be passed upon for us, the selling stockholders, or any underwriters, dealers, or agents by counsel that we will name in the applicable prospectus supplement.

#### EXPERTS
The consolidated financial statements of Waystar Holding Corp. as of December 31, 2024 and 2023, and for each of the years in the three-year period ended December 31, 2024, have been incorporated by reference herein in reliance upon the report of KPMG LLP, independent registered public accounting firm, incorporated by reference herein, and upon the authority of said firm as experts in accounting and auditing.

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[**TABLE OF CONTENTS**](#TOC3)

#### WHERE YOU CAN FIND MORE INFORMATION
We have filed a registration statement on Form S-3 under the Securities Act with respect to the common stock offered by this prospectus with the SEC. This prospectus is a part of the registration statement and does not contain all of the information set forth in the registration statement and its exhibits and schedules, portions of which have been omitted as permitted by the rules and regulations of the SEC. For further information about us and our common stock, you should refer to the registration statement and its exhibits and schedules. Statements contained in this prospectus regarding the contents of any contract or other document referred to in those documents are not necessarily complete, and in each instance we refer you to the copy of the contract or other document filed as an exhibit to the registration statement or other document. Each of these statements is qualified in all respects by this reference.

We are subject to the informational reporting requirements of the Exchange Act and, in accordance with the Exchange Act, we file annual, quarterly and current reports, proxy statements, and other information with the SEC. Our filings with the SEC are available to the public on the SEC's website at http:// www.sec.gov. Those filings are also available to the public on, or accessible through, our website (www.waystar.com) under the heading "Investor Relations." The information we file with the SEC or contained on or accessible through our corporate website or any other website that we may maintain is not part of this prospectus or the registration statement of which this prospectus is a part.

We intend to make available to our common stockholders annual reports containing financial statements audited by an independent registered public accounting firm.

#### INFORMATION INCORPORATED BY REFERENCE
The rules of the SEC allow us to incorporate by reference information we file with the SEC. This means that we are disclosing important information to you by referring to other documents. The information incorporated by reference is considered to be part of this prospectus. To the extent there are inconsistencies between the information contained in this prospectus and the information contained in the documents filed with the SEC prior to the date of this prospectus and incorporated by reference, the information in this prospectus shall be deemed to supersede the information in such incorporated documents. We incorporate by reference the documents listed below (other than any portions thereof, which under the Exchange Act, and applicable SEC rules, are not deemed "filed" under the Exchange Act, unless expressly stated otherwise therein):

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • [our Annual Report on Form 10-K for the fiscal year ended December 31, 2024;](https://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000141057825000148/way-20241231x10k.htm)

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • [our Quarterly Report on Form 10-Q for the quarterly period ended March 31, 2025;](https://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000141057825001048/way-20250331x10q.htm)

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • the information specifically incorporated by reference into [our Annual Report on Form 10-K for the fiscal year ended December 31, 2024](https://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000141057825000148/way-20241231x10k.htm) from our [Definitive Proxy Statement on Schedule 14A filed on April 29, 2025;](https://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000110465925041369/tm253417-5_def14a.htm)

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • our Current Reports on Form 8-K, filed with the SEC on [May 12, 2025](https://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000110465925047008/tm2514730d1_8k.htm) and [June 5, 2025](https://www.sec.gov/ix?doc=/Archives/edgar/data/1990354/000110465925056893/tm2517226d1_8k.htm); and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; • all other documents filed by us under Sections 13(a), 13(c), 14, or 15(d) of the Exchange Act after the date of this prospectus and before the termination of the offerings to which this prospectus relates.

If we have incorporated by reference any statement or information in this prospectus and we subsequently modify that statement or information with information contained in this prospectus, the statement or information previously incorporated in this prospectus is also modified or superseded in the same manner.

We will provide without charge to each person to whom a copy of this prospectus has been delivered, a copy of any and all of these filings. You may request a copy of these filings by calling us at 502-238-9511 or writing to us at:

Investor Relations

Waystar Holding Corp.

1550 Digital Drive, #300

Lehi, Utah 84043

e-mail: investors@waystar.com

Exhibits to any documents incorporated by reference in this prospectus will not be sent, however, unless those exhibits have been specifically referenced in this prospectus.

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### 18,000,000 Shares
![[MISSING IMAGE: lg_waystar-4c.jpg]](lg_waystar-4c.jpg)

### COMMON STOCK

#### PROSPECTUS SUPPLEMENT

### J.P. Morgan

#### September 10, 2025

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## Ex-Filing

?xml version='1.0' encoding='ASCII'? EX-FILING FEES

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| |
|:---|
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; **Calculation of Filing Fee Tables**  |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; **S-3**  |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; **Waystar Holding Corp.**  |

---

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| | | |
|:---|:---|:---|
| | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; **Security Class Title**  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; **Amount of Registration Fee**  |
| **Newly Registered Securities** | **Newly Registered Securities** | **Newly Registered Securities** |
| Fees to be Paid | N/A | N/A |
| Fees Previously Paid | N/A | N/A |
| **Carry Forward Securities** | **Carry Forward Securities** | **Carry Forward Securities** |
| Carry Forward Securities | N/A | N/A |
|  | Total Offering Amounts: | $0.00  |
|  | Total Fees Previously Paid:  | $0.00  |
|  | Total Fee Offsets:  | $0.00  |
|  | Net Fee Due:  | $0.00  |

---

---

| | |
|:---|:---|
| | |
| **Rules 457(b) and 0-11(a)(2)** | **Rules 457(b) and 0-11(a)(2)** |
| Fee Offset Claims | N/A |
| Fee Offset Sources | N/A |
| **Rule 457(p)** | **Rule 457(p)** |
| Fee Offset Claims | N/A |
| Fee Offset Sources | N/A |

---

---

| | | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|:---|
| | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; **Security Type**  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; **Security Class Title**  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; **Amount of Securities Previously Registered**  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; **Maximum Aggregate Offering Price of Securities Previously Registered**  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; **Form Type**  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; **File Number**  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; **Initial Effective Date**  |
| N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A |

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| |
|:---|
| The maximum aggregate offering price of the securities to which the prospectus relates is $709,200,000.00. The prospectus is a final prospectus for the related offering. |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; The filing fee with respect to the securities to which the prospectus relates was previously paid in connection with the Registration Statement on Form S-3 filed by Waystar Holding Corp. on July 14, 2025.  |

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