SUPN · Supernus Pharmaceuticals, Inc.

Transaction made pursuant to a 10b5-1 trading plan adopted December 12, 2025.

Transaction made pursuant to a 10b5-1 trading plan adopted December 12, 2025.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $49.40 to $49.99. The Reporting Person undertakes to provide to Supernus, any security holder of Supernus, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote to this Form 4.

Transaction made pursuant to a 10b5-1 trading plan adopted December 12, 2025.

The option vested in four equal annual installments beginning on February 14, 2019.

Transaction made pursuant to a 10b5-1 trading plan adopted December 12, 2025.

Transaction made pursuant to a 10b5-1 trading plan adopted December 12, 2025.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $49.40 to $50.39. The Reporting Person undertakes to provide to Supernus, any security holder of Supernus, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote to this Form 4.

Transaction made pursuant to a 10b5-1 trading plan adopted December 12, 2025.

Transaction made pursuant to a 10b5-1 trading plan adopted December 12, 2025.

The option vested in four equal annual installments beginning on February 22, 2020.

Transaction made pursuant to a 10b5-1 trading plan adopted December 12, 2025.

Transaction made pursuant to a 10b5-1 trading plan adopted December 12, 2025.

Transaction made pursuant to a 10b5-1 trading plan adopted December 12, 2025.

The option vested in four equal annual installments beginning on February 14, 2019.

Transaction made pursuant to a 10b5-1 trading plan adopted December 12, 2025.

The option vests in four equal annual installments beginning on February 23, 2024.

Transaction made pursuant to a 10b5-1 trading plan adopted December 12, 2025.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $50.40 to $51.15. The Reporting Person undertakes to provide to Supernus, any security holder of Supernus, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote to this Form 4.

Transaction made pursuant to a 10b5-1 trading plan adopted December 12, 2025.

The option vested in four equal annual installments beginning on February 19, 2022.

Transaction made pursuant to a 10b5-1 trading plan adopted December 12, 2025.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $50.35 to $50.77. The Reporting Person undertakes to provide to Supernus, any security holder of Supernus, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote to this Form 4.

Transaction made pursuant to a 10b5-1 trading plan adopted December 12, 2025.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $49.34 to $50.34. The Reporting Person undertakes to provide to Supernus Pharmaceuticals, Inc. ("Supernus"), any security holder of Supernus, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote to this Form 4.

Transaction made pursuant to a 10b5-1 trading plan adopted December 12, 2025.

Transaction made pursuant to a 10b5-1 trading plan adopted December 12, 2025.

Transaction made pursuant to a 10b5-1 trading plan adopted December 12, 2025.

The option vested in four equal annual installments beginning on February 22, 2020.

Transaction made pursuant to a 10b5-1 trading plan adopted December 12, 2025.

Transaction made pursuant to a 10b5-1 trading plan adopted December 12, 2025.

The option vests in four equal annual installments beginning on February 22, 2023.

Transaction made pursuant to a 10b5-1 trading plan adopted December 12, 2025.

Transaction made pursuant to a 10b5-1 trading plan adopted December 12, 2025.

The option vests in four equal annual installments beginning on February 22, 2025.

Transaction made pursuant to a 10b5-1 trading plan adopted December 12, 2025.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $49.63 to $50.62. The Reporting Person undertakes to provide to Supernus Pharmaceuticals, Inc. ("Supernus"), any security holder of Supernus, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote to this Form 4.

The Reporting Person is filing this Form 4 to reflect the fact that 12,500 shares were transferred from the KBT Trust to the Reporting Person on March 13, 2026 without consideration and are now owned directly.

Transaction made pursuant to a 10b5-1 trading plan adopted December 12, 2025.

The Reporting Person is filing this Form 4 to reflect the fact that 12,500 shares were transferred from the KBT Trust to the Reporting Person on March 13, 2026 without consideration and are now owned directly.

Transaction made pursuant to a 10b5-1 trading plan adopted December 12, 2025.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $50.63 to $51.54. The Reporting Person undertakes to provide to Supernus, any security holder of Supernus, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote to this Form 4.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $50.45 to $50.82. The Reporting Person undertakes to provide to Supernus Pharmaceuticals, Inc., any security holder of Supernus, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote to this Form 4.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $53.00 to $53.03. The Reporting Person undertakes to provide to Supernus, any security holder of Supernus, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote to this Form 4.

Represents the number of shares of common stock withheld by the Company to satisfy tax withholding requirements in connection with the vesting of Performance Share Units.

On February 23, 2023, the Reporting Person was awarded Performance Share Units a portion of which vested upon the achievement of individual performance objectives within a defined performance period, which objectives were established on June 12, 2023.

On February 22, 2024, the Reporting Person was awarded Performance Share Units, a portion of which vested upon the achievement of individual performance objectives within a defined performance period, which objectives were established on June 24, 2024.

Represents the number of shares of common stock withheld by the Company to satisfy tax withholding requirements in connection with the vesting of Performance Share Units.

Represents the number of shares of common stock withheld by the Company to satisfy tax withholding requirements in connection with the vesting of Performance Share Units.

On February 22, 2024, the Reporting Person was awarded Performance Share Units, a portion of which vested upon the achievement of individual performance objectives within a defined performance period, which objectives were established on June 24, 2024.

On February 22, 2024, the Reporting Person was awarded Performance Share Units, a portion of which vested upon the achievement of individual performance objectives within a defined performance period, which objectives were established on June 24, 2024.

Represents the number of shares of common stock withheld by the Company to satisfy tax withholding requirements in connection with the vesting of Performance Share Units.

On February 22, 2024, the Reporting Person was awarded Performance Share Units, a portion of which vested upon the achievement of individual performance objectives within a defined performance period, which objectives were established on June 24, 2024.

Represents the number of shares of common stock withheld by the Company to satisfy tax withholding requirements in connection with the vesting of Performance Share Units.

Represents the number of shares of common stock withheld by the Company to satisfy tax withholding requirements in connection with the vesting of Performance Share Units.