Ciena

=== SEC Form 4 — Statement of Changes in Beneficial Ownership === Document Type: 4 Period of Report: 2026-09-24 10b5-1 Pre-arranged Plan: No --- Issuer --- Name: CIENA CORP (CIEN) CIK: 0000936395 --- Reporting Owner --- Name: Claflin Bruce L. CIK: 0001403694 Role: Director --- Non-Derivative Transactions --- [Transaction #1] Security: Common Stock Date: 2026-09-24 | Code: S (Open market sale) Shares: -2,857 | Price: $355.91 Total Value: $1,016,834.87 Shares Owned After: 8,279 | Ownership: I (Indirect) | Nature: By spousal trust Footnotes: [F1] Reflects a contribution of common stock to an exchange fund in exchange for an interest in the exchange fund. The common stock was valued at $355.91 per share for the purpose of determining the size of the interest in the exchange fund to be issued [F2] The beneficiaries of the trust are the reporting person's spouse and children. The reporting person disclaims beneficial ownership of the securities held by the trust. --- Holdings --- [Holding #1] Security: Common Stock Ownership: D (Direct) Footnotes: [F3] Shares reported include unvested Restricted Stock Units (RSUs). --- Footnotes (Complete Index) --- F1: Reflects a contribution of common stock to an exchange fund in exchange for an interest in the exchange fund. The common stock was valued at $355.91 per share for the purpose of determining the size of the interest in the exchange fund to be issued F2: The beneficiaries of the trust are the reporting person's spouse and children. The reporting person disclaims beneficial ownership of the securities held by the trust. F3: Shares reported include unvested Restricted Stock Units (RSUs). --- Signature --- /s/ By: Michele Rankin For: Bruce L. Claflin (2026-09-28)