WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC

Position in CIEN — Ciena Corp

CIK 1644956 CHICAGO, IL

Position in CIEN

as of Mar 31, 2026 · filed May 8, 2026 Compact

Position Value

$154,740,325

-$102,187,619 QoQ

Shares Held

398,579

-63.7% QoQ

Ownership

0.282%

of shares outstanding

% of Portfolio

0.52%

of 13F equity value

Holder Rank

—

not a current holder

Holding Since

Mar 2025

5 quarters on record

Voting authority Sole 95% Shared 0% None 5%

Technology · as of Mar 31, 2026

WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC holds $242,875,115 across 5 Communication Equipment names. CIEN ranks #1 (63.7% of the industry book) .

#	Ticker	Company	Shares	Value (USD)
1	CIEN	Ciena Corp This page	398,579	$154,740,325
2	ADTN	ADTRAN Holdings, Inc.	1,989,530	$25,028,287
3	MSI	Motorola Solutions, Inc.	51,961	$22,549,515
4	BDC	Belden Inc.	190,528	$21,878,330
5	LITE	Lumentum Holdings Inc.	26,579	$18,678,658

5 filing rows on record

Report Date	Value (USD)	Shares	Change	Type	Discretion	Filed
2026-03-31	$154,740,325	398,579	-63.7%	Shares	Sole	2026-05-08
2025-12-31	$256,927,944	1,098,593	-55.0%	Shares	Sole	2026-02-09
2025-09-30	$355,564,154	2,440,888	-9.9%	Shares	Sole	2025-11-12
2025-06-30	$220,285,558	2,708,540	+35.0%	Shares	Sole	2025-07-29
2025-03-31	$121,200,281	2,005,631	—	Shares	Sole	2025-05-09
No filing history on record for this holder in this stock.