Ciena

=== SEC Form 4 — Statement of Changes in Beneficial Ownership === Document Type: 4 Period of Report: 2026-09-20 10b5-1 Pre-arranged Plan: No --- Issuer --- Name: CIENA CORP (CIEN) CIK: 0000936395 --- Reporting Owner --- Name: DiPerna Dino CIK: 0001998460 Role: Officer (EVP & Chief R&D Officer) --- Non-Derivative Transactions --- [Transaction #1] Security: Common Stock Date: 2026-09-20 | Code: F (Payment of exercise/tax) Shares: -204 | Price: $348.80 Total Value: $71,155.20 Shares Owned After: 38,922 | Ownership: D (Direct) Footnotes: [F1] Represents shares withheld to cover payment of the tax liabilities of the reporting person related to a restricted stock unit (RSU) award agreement dated 10/27/2023. Acquisition of the RSU was previously reported in Table I of the reporting person's Form 4 filed on 10/31/2023. [F2] Shares reported include unvested Restricted Stock Units (RSUs) and Performance Stock Units (PSUs). [Transaction #2] Security: Common Stock Date: 2026-09-20 | Code: F (Payment of exercise/tax) Shares: -444 | Price: $348.80 Total Value: $154,867.20 Shares Owned After: 38,478 | Ownership: D (Direct) Footnotes: [F3] Represents shares withheld to cover payment of the tax liabilities of the reporting person related to a restricted stock unit (RSU) award agreement dated 12/13/2022. Acquisition of the RSU was previously reported in Table I of the reporting person's Form 3 filed on 10/31/2023. [F2] Shares reported include unvested Restricted Stock Units (RSUs) and Performance Stock Units (PSUs). [Transaction #3] Security: Common Stock Date: 2026-09-20 | Code: F (Payment of exercise/tax) Shares: -730 | Price: $348.80 Total Value: $254,624.00 Shares Owned After: 37,748 | Ownership: D (Direct) Footnotes: [F4] Represents shares withheld to cover payment of the tax liabilities of the reporting person related to a restricted stock unit (RSU) award agreement dated 12/12/2023. Acquisition of the RSU was previously reported in Table I of the reporting person's Form 4 filed on 12/14/2023. [F2] Shares reported include unvested Restricted Stock Units (RSUs) and Performance Stock Units (PSUs). [Transaction #4] Security: Common Stock Date: 2026-09-20 | Code: F (Payment of exercise/tax) Shares: -428 | Price: $348.80 Total Value: $149,286.40 Shares Owned After: 37,320 | Ownership: D (Direct) Footnotes: [F5] Represents shares withheld to cover payment of the tax liabilities of the reporting person related to a restricted stock unit (RSU) award agreement dated 12/17/2024. Acquisition of the RSU was previously reported in Table I of the reporting person's Form 4 filed on 12/19/2024. [F2] Shares reported include unvested Restricted Stock Units (RSUs) and Performance Stock Units (PSUs). [Transaction #5] Security: Common Stock Date: 2026-09-20 | Code: F (Payment of exercise/tax) Shares: -247 | Price: $348.80 Total Value: $86,153.60 Shares Owned After: 37,073 | Ownership: D (Direct) Footnotes: [F6] Represents shares withheld to cover payment of the tax liabilities of the reporting person related to a restricted stock unit (RSU) award agreement dated 12/16/2025. Acquisition of the RSU was previously reported in Table I of the reporting person's Form 4 filed on 12/18/2025. [F2] Shares reported include unvested Restricted Stock Units (RSUs) and Performance Stock Units (PSUs). --- Footnotes (Complete Index) --- F1: Represents shares withheld to cover payment of the tax liabilities of the reporting person related to a restricted stock unit (RSU) award agreement dated 10/27/2023. Acquisition of the RSU was previously reported in Table I of the reporting person's Form 4 filed on 10/31/2023. F2: Shares reported include unvested Restricted Stock Units (RSUs) and Performance Stock Units (PSUs). F3: Represents shares withheld to cover payment of the tax liabilities of the reporting person related to a restricted stock unit (RSU) award agreement dated 12/13/2022. Acquisition of the RSU was previously reported in Table I of the reporting person's Form 3 filed on 10/31/2023. F4: Represents shares withheld to cover payment of the tax liabilities of the reporting person related to a restricted stock unit (RSU) award agreement dated 12/12/2023. Acquisition of the RSU was previously reported in Table I of the reporting person's Form 4 filed on 12/14/2023. F5: Represents shares withheld to cover payment of the tax liabilities of the reporting person related to a restricted stock unit (RSU) award agreement dated 12/17/2024. Acquisition of the RSU was previously reported in Table I of the reporting person's Form 4 filed on 12/19/2024. F6: Represents shares withheld to cover payment of the tax liabilities of the reporting person related to a restricted stock unit (RSU) award agreement dated 12/16/2025. Acquisition of the RSU was previously reported in Table I of the reporting person's Form 4 filed on 12/18/2025. --- Signature --- /s/ By: Michelle Rankin For: Dino Diperna (2026-09-21)