Question 1

How many shares of CIEN does WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC own?

Accepted Answer

As of 2026-Q1, WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC holds 398,579 shares of CIEN (CIENA CORP).

Question 2

What is WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC's CIEN position worth?

Accepted Answer

As of 2026-Q1, WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC's CIEN position is worth $154.7M.

Question 3

Is WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC buying or selling CIEN?

Accepted Answer

In 2026-Q1, WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC decreased their CIEN position (-63.7% change in shares).

Question 4

When did WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC first buy CIEN?

Accepted Answer

Based on available 13F filings, WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC first reported a position in CIEN in 2025-Q1. They have held the position across 5 quarters.

Quarter	Action	Shares	Change	Value	Weight	Price	Conviction
2026-Q1 Latest	Decreased	398,579	-63.7%	$154.7M	0.5%	$333.07	0
2025-Q4	Decreased	1.1M	-55.0%	$256.9M	0.7%	$238.36	0
2025-Q3	Decreased	2.4M	-9.9%	$355.6M	0.9%	$144.12	0
2025-Q2	Increased	2.7M	+35.0%	$220.3M	0.6%	$82.12	56
2025-Q1	New	2M	—	$121.2M	0.3%	$61.56	50