西耶納公司
MX ˙ BMV ˙ US1717793095
SecurityMX:CIEN / Ciena Corporation
InstitutionAtreides Management, LP
Latest Disclosed Ownership676,807 shares
Latest Disclosed Value $ 262,756,782
Atreides Management, LP reports 52.61% decrease in ownership of CIEN / Ciena Corporation

On May 18, 2026 - Atreides Management, LP filed a 13F-HR form disclosing ownership of 676,807 shares of Ciena Corporation (MX:CIEN) valued at $262,756,782 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 1,428,230 shares of Ciena Corporation. This represents a change in shares of -52.61% during the quarter.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date		 Effective
Date		Form Security Class ID Avg Price
Paid (Est)		 Reported
Shares		 ΔShares ΔShares
(%)		 Reported
Value
(x1000)		 ΔValue
(%)		 Alloc
(%)		 ΔAlloc ΔAlloc (%) Cost Basis
(x1000)		 Unrealized
Gain/Loss
(x1000)
2026-05-18 2026-03-31 13F CIENA COM NEW 171779309 676,807 -751,423 -52.61 262,757 -21.34 5.2528
2026-02-17 2025-12-31 13F CIENA COM NEW 171779309 1,428,230 27,466 1.96 334,020 63.70 4.0816
2025-11-14 2025-09-30 13F CIENA COM NEW 171779309 1,400,764 137,946 10.92 204,049 98.68 3.9739
2025-08-14 2025-06-30 13F CIENA COM NEW 171779309 1,262,818 1,262,818 102,705 2.8500
2025-05-15 2025-03-31 13F CIENA COM NEW 171779309 0 -74,952 -100.00 0 -100.00
2025-02-14 2024-12-31 13F CIENA COM NEW 171779309 74,952 -2,144,259 -96.62 6,357 -95.35 0.1392
2024-11-14 2024-09-30 13F CIENA COM NEW 171779309 2,219,211 -1,373,107 -38.22 136,681 -21.03 3.4800
2024-08-14 2024-06-30 13F CIENA COM NEW 171779309 3,592,318 401,565 12.59 173,078 9.69 5.6522
2024-05-15 2024-03-31 13F CIENA COM NEW 171779309 3,190,753 640,373 25.11 157,783 37.45 3.5816
2024-02-14 2023-12-31 13F CIENA COM NEW 171779309 2,550,380 902,415 54.76 114,793 47.39 3.7704
2023-11-14 2023-09-30 13F CIENA COM NEW 171779309 1,647,965 1,647,965 77,883 2.5457
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.