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: Rothenstein David M CIK: 0001444157 Role: Officer (EVP & Chief Strategy Officer) --- Non-Derivative Transactions --- [Transaction #1] Security: Common Stock Date: 2026-09-20 | Code: F (Payment of exercise/tax) Shares: -679 | Price: $348.80 Total Value: $236,835.20 Shares Owned After: 177,052 | 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 12/13/2022. Acquisition of the RSU was previously reported in Table I of the reporting person's Form 4 filed on 12/15/2022. [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: -204 | Price: $348.80 Total Value: $71,155.20 Shares Owned After: 176,848 | 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 12/13/2022. Acquisition of the RSU was previously reported in Table I of the reporting person's Form 4 filed on 12/15/2022. [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: -811 | Price: $348.80 Total Value: $282,876.80 Shares Owned After: 176,037 | 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 12/12/2023. 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: -436 | Price: $348.80 Total Value: $152,076.80 Shares Owned After: 175,601 | 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 12/17/2024. 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: -220 | Price: $348.80 Total Value: $76,736.00 Shares Owned After: 175,381 | 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 12/16/2025. 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 12/13/2022. Acquisition of the RSU was previously reported in Table I of the reporting person's Form 4 filed on 12/15/2022. 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 12/12/2023. Acquisition of the RSU was previously reported in Table I of the reporting person's Form 4 filed on 12/14/2023. 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 12/17/2024. Acquisition of the RSU was previously reported in Table I of the reporting person's Form 4 filed on 12/19/2024. 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 12/16/2025. 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: David M Rothenstein (2026-09-21)