Ciena

=== SEC Form 4 — Statement of Changes in Beneficial Ownership === Document Type: 4 Period of Report: 2026-08-14 10b5-1 Pre-arranged Plan: Yes --- Issuer --- Name: CIENA CORP (CIEN) CIK: 0000936395 --- Reporting Owner --- Name: Graff Marc D. CIK: 0002080157 Role: Officer (SVP & Chief Financial Officer) --- Non-Derivative Transactions --- [Transaction #1] Security: Common Stock Date: 2026-08-14 | Code: S (Open market sale) Shares: -4,995 | Price: $430.72 Total Value: $2,151,435.41 Shares Owned After: 107,519 | Ownership: D (Direct) Footnotes: [F1] Sales were affected pursuant to Rule 10b5-1 trading plan dated 08/14/2026. [F2] Reflects the weighted average sales price with transactions in a range of sales from $423.3500 to $443.4100. Upon request by the SEC, full information regarding the number of shares sold at each separate sales price will be provided. [F3] Shares reported include unvested Restricted Stock Units (RSUs) --- Footnotes (Complete Index) --- F1: Sales were affected pursuant to Rule 10b5-1 trading plan dated 08/14/2026. F2: Reflects the weighted average sales price with transactions in a range of sales from $423.3500 to $443.4100. Upon request by the SEC, full information regarding the number of shares sold at each separate sales price will be provided. F3: Shares reported include unvested Restricted Stock Units (RSUs) --- Signature --- /s/ By: Michelle Rankin For: Marc D. Graff (2026-08-17)