CIENA CORP (CIEN) Institutional Ownership Changes & 13F Activity

CIENA CORP (CIEN) institutional ownership data tracks hedge funds, asset managers, and other institutional investors based on recent SEC 13F filings (Q1 2026). This page analyzes institutional buying and selling activity, new holdings, and sold-out positions among tracked filers. Notable filers include Lone Pine Capital, Renaissance Technologies LLC, First Eagle U.S. Value, Mairs & Power Growth Fund, and Sequoia Financial Advisors.

Portfolio quarterNameTypeQuantityRemainingReported stock balance
Q3 2015Parnassus Endeavor FundBuy100,0003,100,000$64,232
Q2 2015Parnassus Endeavor FundSell-625,0003,000,000$71,040
Q2 2015Renaissance Technologies LLCBuy315,105363,305$8,603
Q1 2015Parnassus Endeavor FundSell-100,0003,625,000$69,999
Q1 2015Renaissance Technologies LLCBuy30,69548,200$931
Q4 2014Renaissance Technologies LLCSell-1,651,00017,505$340
Q4 2014Parnassus Endeavor FundBuy1,385,0003,725,000$72,302
Q3 2014Parnassus Endeavor FundBuy140,0002,340,000$39,125
Q3 2014Dodge & Cox Stock FundBuy11,23011,230$188
Q2 2014Parnassus Endeavor FundSell-31,6312,200,000$47,652
Q1 2014Parnassus Endeavor FundSell-228,7632,231,631$50,747
Q4 2013Parnassus Endeavor FundBuy2,3672,460,394$58,877
Q3 2013Parnassus Endeavor FundSell-1,143,5452,458,027$61,402
Q3 2013Renaissance Technologies LLCBuy537,1001,668,505$41,728
Q2 2013Parnassus Endeavor FundBuy3,601,5723,601,572$69,943
Q2 2013Renaissance Technologies LLCBuy1,131,4051,131,405$21,983

Frequently asked questions about CIEN activity

  • Which institutional owners are buying CIEN?

    Institutional owners buying CIEN include investors who have either initiated new positions or increased their existing holdings based on recent SEC 13F filings. The activity table above highlights which funds added shares in the latest reporting periods and how their positions changed over time.

  • What does "buy" mean in CIEN activity?

    "Buy" means an investor increased their reported position in CIEN compared to the prior reporting period. This reflects growing exposure to CIENA CORP (CIEN) rather than necessarily a brand-new position (though new positions also appear as buys when prior quantity was zero).

  • Is institutional interest in CIEN increasing?

    Institutional interest in CIEN can be assessed by comparing the number of tracked funds adding or increasing positions versus those trimming or exiting across the periods shown. A higher number of additions typically signals increasing participation among large filers, but it should be read alongside position sizes and the full table.

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