WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC

Position in ADTN — ADTRAN Holdings, Inc.

CIK 1644956 CHICAGO, IL

Position in ADTN

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

Position Value

$25,028,287

+$3,489,071 QoQ

Shares Held

1,989,530

-19.7% QoQ

Ownership

2.46%

of shares outstanding

% of Portfolio

0.08%

of 13F equity value

Holder Rank

—

not a current holder

Holding Since

Jun 2023

12 quarters on record

Voting authority Sole 69% Shared 0% None 31%

Technology · as of Mar 31, 2026

WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC holds $242,875,115 across 5 Communication Equipment names. ADTN ranks #2 (10.3% of the industry book) .

#	Ticker	Company	Shares	Value (USD)
1	CIEN	Ciena Corp	398,579	$154,740,325
2	ADTN	ADTRAN Holdings, Inc. This page	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

12 filing rows on record

Report Date	Value (USD)	Shares	Change	Type	Discretion	Filed
2026-03-31	$25,028,287	1,989,530	-19.7%	Shares	Sole	2026-05-08
2025-12-31	$21,539,216	2,478,621	-9.4%	Shares	Sole	2026-02-09
2025-09-30	$25,667,713	2,736,430	-5.7%	Shares	Sole	2025-11-12
2025-06-30	$26,035,658	2,902,526	-7.5%	Shares	Sole	2025-07-29
2025-03-31	$27,372,978	3,139,103	-32.5%	Shares	Sole	2025-05-09
2024-12-31	$38,710,801	4,647,155	+2.5%	Shares	Sole	2025-02-10
2024-09-30	$26,875,762	4,532,169	+2.1%	Shares	Sole	2024-11-08
2024-06-30	$23,339,603	4,437,187	-0.4%	Shares	Sole	2024-08-08
2024-03-31	$24,241,004	4,456,067	+22.5%	Shares	Sole	2024-05-08
2023-12-31	$26,705,158	3,638,305	+51.2%	Shares	Sole	2024-02-09
2023-09-30	$19,800,054	2,405,839	+57.2%	Shares	Sole	2023-11-09
2023-06-30	$16,118,260	1,530,699	—	Shares	Sole	2023-08-11
No filing history on record for this holder in this stock.