Sinclair III Eric L. (Ric)

SEC source: 0001998250-26-000002 · wk-form4_1769116455.xml · derivative · entry 5

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 6,141

Underlying: Common Stock · 32,663 shares

Expires 2027-11-01

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: These options are currently vested.

SEC source: 0001998250-26-000002 · wk-form4_1769116455.xml · derivative · entry 4

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 173,938

Underlying: Common Stock · 7,562 shares

Expires 2030-08-09

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 on August 9, 2020 of which 50% of the option vests in five substantially equal annual installments commencing on August 9, 2021 and the remaining 50% of the option vests upon achievement of certain specified performance-based vesting criteria.

SEC source: 0001998250-26-000002 · wk-form4_1769116455.xml · nonDerivative · entry 3

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 474,826

F3 · 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 $30.00 to $30.23, 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: Includes unvested RSUs.

F2 · balance_after: These transactions occurred automatically pursuant to a plan adopted by the Reporting Person on August 24, 2025 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

SEC source: 0001998250-26-000002 · wk-form4_1769116455.xml · nonDerivative · entry 2

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 515,051

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: Includes unvested RSUs.

F2 · balance_after: These transactions occurred automatically pursuant to a plan adopted by the Reporting Person on August 24, 2025 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

SEC source: 0001998250-26-000002 · wk-form4_1769116455.xml · nonDerivative · entry 1

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 482,388

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: Includes unvested RSUs.

F2 · balance_after: These transactions occurred automatically pursuant to a plan adopted by the Reporting Person on August 24, 2025 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

SEC source: 0001998250-25-000015 · wk-form4_1766507528.xml · derivative · entry 3

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 38,804

Underlying: Common Stock · 9,701 shares

Expires 2027-11-01

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: These options are currently vested.

SEC source: 0001998250-25-000015 · wk-form4_1766507528.xml · nonDerivative · entry 2

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 474,826

F3 · 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 $32.57 to $32.98, 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: Includes unvested RSUs.

F2 · balance_after: These transactions occurred automatically pursuant to a plan adopted by the Reporting Person on February 19, 2025 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

SEC source: 0001998250-25-000015 · wk-form4_1766507528.xml · nonDerivative · entry 1

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 484,527

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: Includes unvested RSUs.

F2 · balance_after: These transactions occurred automatically pursuant to a plan adopted by the Reporting Person on February 19, 2025 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

SEC source: 0001998250-25-000013 · wk-form4_1763740888.xml · derivative · entry 3

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 48,505

Underlying: Common Stock · 9,701 shares

Expires 2027-11-01

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: These options are currently vested.

SEC source: 0001998250-25-000013 · wk-form4_1763740888.xml · nonDerivative · entry 2

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 474,826

F3 · 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 $34.79 to $35.80, 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: Includes unvested RSUs.

F2 · balance_after: These transactions occurred automatically pursuant to a plan adopted by the Reporting Person on February 19, 2025 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

SEC source: 0001998250-25-000013 · wk-form4_1763740888.xml · nonDerivative · entry 1

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 484,527

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: Includes unvested RSUs.

F2 · balance_after: These transactions occurred automatically pursuant to a plan adopted by the Reporting Person on February 19, 2025 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

SEC source: 0001998250-25-000011 · wk-form4_1761077378.xml · derivative · entry 3

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 58,206

Underlying: Common Stock · 9,701 shares

Expires 2027-11-01

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: These options are currently vested.

SEC source: 0001998250-25-000011 · wk-form4_1761077378.xml · nonDerivative · entry 2

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 474,826

F3 · 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 $36.52 to $37.86, 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: Includes unvested RSUs.

F2 · balance_after: These transactions occurred automatically pursuant to a plan adopted by the Reporting Person on February 19, 2025 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

SEC source: 0001998250-25-000011 · wk-form4_1761077378.xml · nonDerivative · entry 1

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 484,527

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: Includes unvested RSUs.

F2 · balance_after: These transactions occurred automatically pursuant to a plan adopted by the Reporting Person on February 19, 2025 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

SEC source: 0001998250-25-000008 · wk-form4_1758733435.xml · derivative · entry 3

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 67,907

Underlying: Common Stock · 9,701 shares

Expires 2027-11-01

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: These options are currently vested.

SEC source: 0001998250-25-000008 · wk-form4_1758733435.xml · nonDerivative · entry 2

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 474,826

F3 · 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 $37.24 to $38.14, 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: Includes unvested RSUs.

F2 · balance_after: These transactions occurred automatically pursuant to a plan adopted by the Reporting Person on February 19, 2025 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

SEC source: 0001998250-25-000008 · wk-form4_1758733435.xml · nonDerivative · entry 1

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 484,527

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: Includes unvested RSUs.

F2 · balance_after: These transactions occurred automatically pursuant to a plan adopted by the Reporting Person on February 19, 2025 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

SEC source: 0001998250-25-000006 · wk-form4_1757526443.xml · derivative · entry 4

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 77,608

Underlying: Common Stock · 19,404 shares

Expires 2027-11-01

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: These options are currently vested.

SEC source: 0001998250-25-000006 · wk-form4_1757526443.xml · nonDerivative · entry 3

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 474,826

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 $40.00 to $40.25, 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: Includes unvested RSUs.

F3 · balance_after: These transactions occurred automatically pursuant to a plan adopted by the Reporting Person on February 19, 2025 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

SEC source: 0001998250-25-000006 · wk-form4_1757526443.xml · nonDerivative · entry 2

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 494,230

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: Includes unvested RSUs.

F3 · balance_after: These transactions occurred automatically pursuant to a plan adopted by the Reporting Person on February 19, 2025 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

SEC source: 0001998250-25-000004 · wk-form4_1755724162.xml · derivative · entry 3

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 97,012

Underlying: Common Stock · 9,702 shares

Expires 2027-11-01

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: These options are currently vested.

SEC source: 0001998250-25-000004 · wk-form4_1755724162.xml · nonDerivative · entry 2

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 490,870

F3 · 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 $34.73 to $35.28, 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 February 19, 2025 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

F2 · balance_after: Includes unvested RSUs.

SEC source: 0001998250-25-000004 · wk-form4_1755724162.xml · nonDerivative · entry 1

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 500,572

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 February 19, 2025 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

F2 · balance_after: Includes unvested RSUs.

SEC source: 0001998250-25-000001 · wk-form4_1753225425.xml · derivative · entry 3

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 106,714

Underlying: Common Stock · 9,702 shares

Expires 2027-11-01

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: These options are currently vested.

SEC source: 0001998250-25-000001 · wk-form4_1753225425.xml · nonDerivative · entry 2

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 490,870

F3 · 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 $36.41 to $37.42, 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 February 19, 2025 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

F2 · balance_after: Includes unvested RSUs.

SEC source: 0001998250-25-000001 · wk-form4_1753225425.xml · nonDerivative · entry 1

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 500,572

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 February 19, 2025 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

F2 · balance_after: Includes unvested RSUs.

SEC source: 0001104659-25-062657 · tm2519025-1_4seq1.xml · derivative · entry 3

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 116,416

Underlying: Common Stock · 9,702 shares

Expires 2027-11-01

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: These options are currently vested.

SEC source: 0001104659-25-062657 · tm2519025-1_4seq1.xml · nonDerivative · entry 2

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 490,870

F3 · 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 $40.00 to $40.4050, 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 February 19, 2025 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

F2 · balance_after: Includes unvested RSUs.

SEC source: 0001104659-25-062657 · tm2519025-1_4seq1.xml · nonDerivative · entry 1

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 500,572

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 February 19, 2025 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

F2 · balance_after: Includes unvested RSUs.

SEC source: 0001104659-25-061662 · tm2518589-1_4seq1.xml · derivative · entry 3

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 126,118

Underlying: Common Stock · 9,702 shares

Expires 2027-11-01

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: These options are currently vested.

SEC source: 0001104659-25-061662 · tm2518589-1_4seq1.xml · nonDerivative · entry 2

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 490,870

F3 · 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 $37.65 to $38.09, 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 February 19, 2025 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

F2 · balance_after: Includes unvested RSUs.

SEC source: 0001104659-25-061662 · tm2518589-1_4seq1.xml · nonDerivative · entry 1

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 500,572

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 February 19, 2025 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

F2 · balance_after: Includes unvested RSUs.

SEC source: 0001998250-25-000006 · wk-form4_1757526443.xml · nonDerivative · entry 1

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 474,826

F1 · balance_after: Includes unvested RSUs.

F2 · 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: 0001104659-25-055422 · tm2516824-1_4seq1.xml · derivative · entry 3

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 135,820

Underlying: Common Stock · 9,702 shares

Expires 2027-11-01

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: These options are currently vested.

SEC source: 0001104659-25-055422 · tm2516824-1_4seq1.xml · nonDerivative · entry 2

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 490,870

F1 · balance_after: These transactions occurred automatically pursuant to a plan adopted by the Reporting Person on February 19, 2025 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

F2 · balance_after: Includes unvested RSUs.

SEC source: 0001104659-25-055422 · tm2516824-1_4seq1.xml · nonDerivative · entry 1

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 500,572

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 February 19, 2025 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

F2 · balance_after: Includes unvested RSUs.

SEC source: 0001104659-25-052088 · tm2515964-1_4seq1.xml · derivative · entry 4

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 145,522

Underlying: Common Stock · 9,702 shares

Expires 2027-11-01

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: These options are currently vested.

SEC source: 0001104659-25-052088 · tm2515964-1_4seq1.xml · nonDerivative · entry 3

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 490,870

F1 · balance_after: These transactions occurred automatically pursuant to a plan adopted by the Reporting Person on February 19, 2025 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

F3 · balance_after: Includes unvested RSUs.

SEC source: 0001104659-25-052088 · tm2515964-1_4seq1.xml · nonDerivative · entry 2

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 490,907

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 $38.53 to $39.50, 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 February 19, 2025 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

F3 · balance_after: Includes unvested RSUs.

SEC source: 0001104659-25-052088 · tm2515964-1_4seq1.xml · nonDerivative · entry 1

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 500,572

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 February 19, 2025 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

F3 · balance_after: Includes unvested RSUs.

SEC source: 0001104659-25-031489 · tm2511308-2_4seq1.xml · nonDerivative · entry 1

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 490,870

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: 0001104659-24-070868 · tm2416795-2_4seq1.xml · nonDerivative · entry 1

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 173,913

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: 0001104659-24-070868 · tm2416795-2_4seq1.xml · derivative · entry 3

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 434,782

Underlying: Common Stock · 434,782 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: 0001104659-24-070868 · tm2416795-2_4seq1.xml · derivative · entry 2

Sinclair III Eric L. (Ric) · CIK 0001998250 · Chief Business Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 72,600

Underlying: Common Stock · 72,600 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.