Ciena

=== SEC Form 4 — Statement of Changes in Beneficial Ownership === Document Type: 4 Period of Report: 2026-08-17 10b5-1 Pre-arranged Plan: Yes --- Issuer --- Name: CIENA CORP (CIEN) CIK: 0000936395 --- Reporting Owner --- Name: SMITH GARY B CIK: 0001032553 Role: Director, Officer (President, CEO) --- Non-Derivative Transactions --- [Transaction #1] Security: Common Stock Date: 2026-08-17 | Code: S (Open market sale) Shares: -2,952 | Price: $447.78 Total Value: $1,321,840.36 Shares Owned After: 246,030 | Ownership: D (Direct) Footnotes: [F1] Sales were affected pursuant to Rule 10b5-1 trading plan dated 10/04/2025. [F2] Reflects the weighted average sales price with transactions in a range of sales from $429.9900 to $457.8650. 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) and Performance Stock Units (PSUs). --- Footnotes (Complete Index) --- F1: Sales were affected pursuant to Rule 10b5-1 trading plan dated 10/04/2025. F2: Reflects the weighted average sales price with transactions in a range of sales from $429.9900 to $457.8650. 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) and Performance Stock Units (PSUs). --- Signature --- /s/ By: Michelle Rankin For: Gary B. Smith (2026-08-18)