Miller Melissa F. (Missy)

SEC source: 0001998251-26-000004 · wk-form4_1781038775.xml · nonDerivative · entry 1

Miller Melissa F. (Missy) · CIK 0001998251 · Chief Marketing Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 252,077

F1 · balance_after: The transaction represents shares of common stock withheld to pay taxes upon vesting of Non-Qualified Stock Options granted to the Reporting Person on June 6, 2024. The number of shares withheld was determined based on the actual sale price of shares sold on June 9, 2026 pursuant to a sell-to-cover transaction.

F2 · balance_after: Includes unvested RSUs.

SEC source: 0001998251-26-000002 · wk-form4_1773269097.xml · nonDerivative · entry 1

Miller Melissa F. (Missy) · CIK 0001998251 · Chief Marketing Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 254,964

F1 · shares: Reflects a grant of restricted stock units ("RSUs") which vests in four equal annual installments from the initial grant date through March 1, 2030. Each RSU represents a contingent right to receive one share of common stock, $0.01 par value per share (the "Common Stock") upon settlement.

F2 · balance_after: Includes unvested RSUs.

SEC source: 0001998251-25-000009 · wk-form4_1764169966.xml · derivative · entry 3

Miller Melissa F. (Missy) · CIK 0001998251 · Chief Marketing Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 28,750

Underlying: Common Stock · 3,400 shares

Expires 2030-08-17

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F3 · derivative.exercise_date: Options granted August 17, 2020 of which 50% of the option vests in five substantially equal annual installments commencing on August 17, 2021 and the remaining 50% of the option vests upon achievement of certain specified performance-based vesting criteria.

F1 · balance_after: These transactions occurred automatically pursuant to a plan adopted by the Reporting Person on November 20, 2024 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

SEC source: 0001998251-25-000009 · wk-form4_1764169966.xml · nonDerivative · entry 2

Miller Melissa F. (Missy) · CIK 0001998251 · Chief Marketing Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 193,261

F1 · balance_after: These transactions occurred automatically pursuant to a plan adopted by the Reporting Person on November 20, 2024 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

F2 · balance_after: Includes unvested RSUs.

SEC source: 0001998251-25-000009 · wk-form4_1764169966.xml · nonDerivative · entry 1

Miller Melissa F. (Missy) · CIK 0001998251 · Chief Marketing Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 196,661

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · balance_after: These transactions occurred automatically pursuant to a plan adopted by the Reporting Person on November 20, 2024 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

F2 · balance_after: Includes unvested RSUs.

SEC source: 0001998251-25-000006 · wk-form4_1756414968.xml · derivative · entry 4

Miller Melissa F. (Missy) · CIK 0001998251 · Chief Marketing Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 32,150

Underlying: Common Stock · 3,400 shares

Expires 2030-08-17

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F5 · derivative.exercise_date: Options granted August 17, 2020 of which 50% of the option vests in five substantially equal annual installments commencing on August 17, 2021 and the remaining 50% of the option vests upon achievement of certain specified performance-based vesting criteria.

F2 · balance_after: These transactions occurred automatically pursuant to a plan adopted by the Reporting Person on November 20, 2024 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

SEC source: 0001998251-25-000006 · wk-form4_1756414968.xml · nonDerivative · entry 3

Miller Melissa F. (Missy) · CIK 0001998251 · Chief Marketing Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 193,261

F4 · price: The price reported in Column 4 is a weighted average price. These shares of common stock, par value $0.01 per share ("Common Stock") of Waystar Holding Corp. (the "Issuer") were sold in multiple transactions ranging from $37.00 to $37.03, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares of Common Stock sold at each separate price in the range set forth in this footnote.

F2 · balance_after: These transactions occurred automatically pursuant to a plan adopted by the Reporting Person on November 20, 2024 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

F3 · balance_after: Includes unvested RSUs.

SEC source: 0001998251-25-000006 · wk-form4_1756414968.xml · nonDerivative · entry 2

Miller Melissa F. (Missy) · CIK 0001998251 · Chief Marketing Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 196,661

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F2 · balance_after: These transactions occurred automatically pursuant to a plan adopted by the Reporting Person on November 20, 2024 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

F3 · balance_after: Includes unvested RSUs.

SEC source: 0001104659-25-058881 · tm2517879-2_4seq1.xml · nonDerivative · entry 1

Miller Melissa F. (Missy) · CIK 0001998251 · Chief Marketing Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 192,484

F2 · price: The price reported in Column 4 is a weighted average price. These shares of common stock, par value $0.01 per share ("Common Stock") of Waystar Holding Corp. (the "Issuer") were sold in multiple transactions ranging from $40.47 to $40.99, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares of Common Stock sold at each separate price in the range set forth in this footnote.

F1 · balance_after: These transactions occurred automatically pursuant to a plan adopted by the Reporting Person on November 20, 2024 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

F3 · balance_after: Includes unvested RSU's.

SEC source: 0001998251-25-000006 · wk-form4_1756414968.xml · nonDerivative · entry 1

Miller Melissa F. (Missy) · CIK 0001998251 · Chief Marketing Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 193,261

F1 · balance_after: This transaction was not timely filed. The transaction represents shares of common stock withheld to pay taxes upon vesting of Non-Qualified Stock Options granted to the Reporting Person on June 6, 2024. The number of shares withheld was determined on June 6, 2025, based on the closing price of WAY common stock on that date. In addition, the total number of shares beneficially owned following the reported transaction reflects a correction to prior filings to account for an earlier misclassification of an option exercise. The ending balance reported herein is accurate and reflects the Reporting Person's current holdings.

SEC source: 0001104659-25-049882 · tm2515316-1_4seq1.xml · nonDerivative · entry 2

Miller Melissa F. (Missy) · CIK 0001998251 · Chief Marketing Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 198,556

F1 · balance_after: These transactions occurred automatically pursuant to a plan adopted by the Reporting Person on November 20, 2024 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

F3 · balance_after: Includes unvested RSUs.

SEC source: 0001104659-25-049882 · tm2515316-1_4seq1.xml · nonDerivative · entry 1

Miller Melissa F. (Missy) · CIK 0001998251 · Chief Marketing Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 198,656

F2 · price: The price reported in Column 4 is a weighted average price. These shares of common stock, par value $0.01 per share ("Common Stock") of Waystar Holding Corp. (the "Issuer") were sold in multiple transactions ranging from $38.89 to $39.45, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares of Common Stock sold at each separate price in the range set forth in this footnote.

F1 · balance_after: These transactions occurred automatically pursuant to a plan adopted by the Reporting Person on November 20, 2024 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

F3 · balance_after: Includes unvested RSUs.

SEC source: 0001998251-25-000004 · wk-form4a_1756414855.xml · derivative · entry 3

Miller Melissa F. (Missy) · CIK 0001998251 · Chief Marketing Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 35,550

Underlying: Common Stock · 3,400 shares

Expires 2030-08-17

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · kind: This Form 4/A is being filed to correct the original Form 4 filed on May 15, 2025 ("Original Form 4"). The Original Form 4 inadvertently omitted the reporting of an option exercise that occurred on May 15, 2025, immediately prior to the sale of shares reported in that filing. The number of shares sold as reported in the Original Form 4 was correct; however, the ending total was incorrect due to the omission of the option exercise. This amendment adds the previously unreported option exercise transaction and restates the sell of shares reported in the Original Form 4 in a single combined row, consistent with other filings for the Reporting Owner. No other changes have been made to the Original Form 4.

F5 · derivative.exercise_date: Options granted August 17, 2020 of which 50% of the option vests in five substantially equal annual installments commencing on August 17, 2021 and the remaining 50% of the option vests upon achievement of certain specified performance-based vesting criteria.

F2 · balance_after: These transactions occurred automatically pursuant to a plan adopted by the Reporting Person on November 20, 2024 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

SEC source: 0001998251-25-000004 · wk-form4a_1756414855.xml · nonDerivative · entry 2

Miller Melissa F. (Missy) · CIK 0001998251 · Chief Marketing Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 201,956

F1 · kind: This Form 4/A is being filed to correct the original Form 4 filed on May 15, 2025 ("Original Form 4"). The Original Form 4 inadvertently omitted the reporting of an option exercise that occurred on May 15, 2025, immediately prior to the sale of shares reported in that filing. The number of shares sold as reported in the Original Form 4 was correct; however, the ending total was incorrect due to the omission of the option exercise. This amendment adds the previously unreported option exercise transaction and restates the sell of shares reported in the Original Form 4 in a single combined row, consistent with other filings for the Reporting Owner. No other changes have been made to the Original Form 4.

F4 · price: The price reported in Column 4 is a weighted average price. These shares of common stock, par value $0.01 per share ("Common Stock") of Waystar Holding Corp. (the "Issuer") were sold in multiple transactions ranging from $38.89 to $40.06, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares of Common Stock sold at each separate price in the range set forth in this footnote.

F2 · balance_after: These transactions occurred automatically pursuant to a plan adopted by the Reporting Person on November 20, 2024 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

F3 · balance_after: Includes unvested RSUs.

SEC source: 0001998251-25-000004 · wk-form4a_1756414855.xml · nonDerivative · entry 1

Miller Melissa F. (Missy) · CIK 0001998251 · Chief Marketing Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 205,356

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · kind: This Form 4/A is being filed to correct the original Form 4 filed on May 15, 2025 ("Original Form 4"). The Original Form 4 inadvertently omitted the reporting of an option exercise that occurred on May 15, 2025, immediately prior to the sale of shares reported in that filing. The number of shares sold as reported in the Original Form 4 was correct; however, the ending total was incorrect due to the omission of the option exercise. This amendment adds the previously unreported option exercise transaction and restates the sell of shares reported in the Original Form 4 in a single combined row, consistent with other filings for the Reporting Owner. No other changes have been made to the Original Form 4.

F2 · balance_after: These transactions occurred automatically pursuant to a plan adopted by the Reporting Person on November 20, 2024 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

F3 · balance_after: Includes unvested RSUs.

SEC source: 0001104659-25-031491 · tm2511308d4_4seq1.xml · nonDerivative · entry 1

Miller Melissa F. (Missy) · CIK 0001998251 · Chief Marketing Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 201,956

F1 · kind: Reflects a grant of restricted stock units ("RSUs") which vest over 4 years, with 40% vesting in year 3 and 60% vesting in year 4. Each RSU represents a contingent right to receive one share of common stock, $0.01 par value per share (the "Common Stock") upon settlement.

F2 · balance_after: Includes unvested RSUs.

SEC source: 0001104659-25-016966 · tm257484-1_4seq1.xml · derivative · entry 4

Miller Melissa F. (Missy) · CIK 0001998251 · Chief Marketing Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 38,950

Underlying: Common Stock · 3,400 shares

Expires 2030-08-17

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F4 · derivative.exercise_date: Options granted August 17, 2020 of which 50% of the option vests in five substantially equal annual installments commencing on August 17, 2021 and the remaining 50% of the option vests upon achievement of certain specified performance-based vesting criteria.

F1 · balance_after: These transactions occurred automatically pursuant to a plan adopted by the Reporting Person on November 20, 2024 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

SEC source: 0001104659-25-016966 · tm257484-1_4seq1.xml · nonDerivative · entry 3

Miller Melissa F. (Missy) · CIK 0001998251 · Chief Marketing Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 43,478

F3 · price: The price reported in Column 4 is a weighted average price. These shares of Common Stock of the Issuer were sold in multiple transactions ranging from $41.76 to $42.59, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares of Common Stock sold at each separate price in the range set forth in this footnote.

F1 · balance_after: These transactions occurred automatically pursuant to a plan adopted by the Reporting Person on November 20, 2024 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

SEC source: 0001104659-25-016966 · tm257484-1_4seq1.xml · nonDerivative · entry 2

Miller Melissa F. (Missy) · CIK 0001998251 · Chief Marketing Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 46,678

F2 · price: The price reported in Column 4 is a weighted average price. These shares of common stock, par value $0.01 per share ("Common Stock") of Waystar Holding Corp. (the "Issuer") were sold in multiple transactions ranging from $40.76 to $41.52, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares of Common Stock sold at each separate price in the range set forth in this footnote.

F1 · balance_after: These transactions occurred automatically pursuant to a plan adopted by the Reporting Person on November 20, 2024 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

SEC source: 0001104659-25-016966 · tm257484-1_4seq1.xml · nonDerivative · entry 1

Miller Melissa F. (Missy) · CIK 0001998251 · Chief Marketing Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 46,878

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · balance_after: These transactions occurred automatically pursuant to a plan adopted by the Reporting Person on November 20, 2024 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

SEC source: 0001104659-24-070869 · tm2416795-8_4seq1.xml · nonDerivative · entry 1

Miller Melissa F. (Missy) · CIK 0001998251 · Chief Marketing Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 43,478

F1 · kind: Reflects a grant of restricted stock units ("RSUs") which vest in five substantially equal annual installments commencing on June 6, 2025. Each RSU represents a contingent right to receive one share of common stock, $0.01 par value per share (the "Common Stock") upon settlement.

F2 · balance_after: Includes unvested RSUs.

SEC source: 0001104659-24-070869 · tm2416795-8_4seq1.xml · derivative · entry 3

Miller Melissa F. (Missy) · CIK 0001998251 · Chief Marketing Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 108,695

Underlying: Common Stock · 108,695 shares

Expires 2034-06-06

F4 · kind: On June 6, 2024 reporting person was granted options to purchase shares of Common Stock which vest in five substantially equal annual installments commencing on June 6, 2025. Such securities were originally included on the Form 3 filed by the reporting person on June 7, 2024.

F4 · derivative.exercise_date: On June 6, 2024 reporting person was granted options to purchase shares of Common Stock which vest in five substantially equal annual installments commencing on June 6, 2025. Such securities were originally included on the Form 3 filed by the reporting person on June 7, 2024.

SEC source: 0001104659-24-070869 · tm2416795-8_4seq1.xml · derivative · entry 2

Miller Melissa F. (Missy) · CIK 0001998251 · Chief Marketing Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 30,250

Underlying: Common Stock · 30,250 shares

Expires 2034-05-01

F3 · kind: On May 1, 2024 reporting person was granted options to purchase shares of Common Stock which vest in three substantially equal annual installments commencing on May 1, 2025. Such securities were originally included on the Form 3 filed by the reporting person on June 7, 2024. Reflects the 0.605-for-1 reverse stock split which became effective on May 15, 2024.

F3 · derivative.exercise_date: On May 1, 2024 reporting person was granted options to purchase shares of Common Stock which vest in three substantially equal annual installments commencing on May 1, 2025. Such securities were originally included on the Form 3 filed by the reporting person on June 7, 2024. Reflects the 0.605-for-1 reverse stock split which became effective on May 15, 2024.