Mason Hawkins - Longleaf Partners 13F Activity & Position Changes (Q1 2026)

According to the SEC 13F filed on May 15, 2026, the Longleaf Partners portfolio showed several notable changes in holdings as of quarter-end Mar 31, 2026. The activity included new positions, additions to existing holdings, reductions, and complete exits, providing a clear view of how the portfolio evolved during the quarter.

During Q1 2026, the filing reported:

New Buys - None reported

Increases - Albertsons Companies, Inc., Clearwater Paper Corporation, New Oriental Education & Techno, Empire State Realty Trust, Inc., Fortune Brands Innovations, Inc, and 6 more

Reductions - ACM Research, Inc., Alexander's, Inc., Avantor, Inc., Bio-Rad Laboratories, Inc., Cardinal Health, Inc., and 10 more

Complete Exits - Walt Disney Company (The), Louisiana-Pacific Corporation, Owens & Minor, Inc., PotlatchDeltic Corporation - Co

These updates highlight how the portfolio adjusted across different sectors and market conditions, offering insights into allocation shifts and investment trends.

Date	Symbol	Name	Type	Change Qty	% Change	Value	Remaining
Q1 2026	ACI Albertsons Companies, Inc.	Albertsons Companies, Inc.	Buy	+1,253,089	+20.3%	$126.43M	7,419,801
Q1 2026	ACMR ACM Research, Inc.	ACM Research, Inc.	Sell	-897,281	-53.4%	$30.81M	782,900
Q1 2026	ALX Alexander's, Inc.	Alexander's, Inc.	Sell	-23,699	-19.3%	$23.39M	99,013
Q1 2026	AVTR Avantor, Inc.	Avantor, Inc.	Sell	-28,306	-0.8%	$27.60M	3,520,212
Q1 2026	BIO Bio-Rad Laboratories, Inc.	Bio-Rad Laboratories, Inc.	Sell	-64,826	-28.5%	$45.38M	162,804
Q1 2026	CAH Cardinal Health, Inc.	Cardinal Health, Inc.	Sell	-1,312	-15.2%	$1.55M	7,337
Q1 2026	CLW Clearwater Paper Corporation	Clearwater Paper Corporation	Buy	+144,561	+10.5%	$21.94M	1,525,491
Q1 2026	CNX CNX Resources Corporation	CNX Resources Corporation	Sell	-721,713	-15.2%	$154.74M	4,014,111
Q1 2026	DIS Walt Disney Company (The)	Walt Disney Company (The)	Sell - Position Exit	-317,175	-100.0%	$0.00	-
Q1 2026	EDU New Oriental Education & Techno	New Oriental Education & Techno	Buy	+142,719	+37.6%	$29.58M	522,280
Q1 2026	ESRT Empire State Realty Trust, Inc.	Empire State Realty Trust, Inc.	Buy	+2,769,081	+74.8%	$33.66M	6,473,317
Q1 2026	FBIN Fortune Brands Innovations, Inc	Fortune Brands Innovations, Inc	Buy	+975,182	+82.8%	$83.91M	2,153,285
Q1 2026	FDX FedEx Corporation	FedEx Corporation	Sell	-111,627	-31.1%	$88.15M	247,495
Q1 2026	FIS Fidelity National Information S	Fidelity National Information S	Buy	+205,352	+33.0%	$38.82M	827,501
Q1 2026	G9618E107 White Mountains	White Mountains	Sell	-12,788	-40.4%	$41.44M	18,864
Q1 2026	GHC Graham Holdings Company	Graham Holdings Company	Buy	+2,039	+5.7%	$39.92M	37,760
Q1 2026	IAC IAC Inc.	IAC Inc.	Buy	+33,389	+0.8%	$161.03M	4,022,729
Q1 2026	KHC The Kraft Heinz Company	The Kraft Heinz Company	Sell	-539,403	-12.0%	$88.81M	3,948,713
Q1 2026	LPX Louisiana-Pacific Corporation	Louisiana-Pacific Corporation	Sell - Position Exit	-272,123	-100.0%	$0.00	-
Q1 2026	MAT Mattel, Inc.	Mattel, Inc.	Buy	+4,241,829	+49.5%	$186.16M	12,812,157
Q1 2026	MGM MGM Resorts International	MGM Resorts International	Sell	-370,408	-18.2%	$61.55M	1,662,961
Q1 2026	OMI Owens & Minor, Inc.	Owens & Minor, Inc.	Sell - Position Exit	-181,735	-100.0%	$0.00	-
Q1 2026	PCH PotlatchDeltic Corporation - Co	PotlatchDeltic Corporation - Co	Sell - Position Exit	-3,162,963	-100.0%	$0.00	-
Q1 2026	PYPL PayPal Holdings, Inc.	PayPal Holdings, Inc.	Sell	-531,611	-95.9%	$1.02M	22,463
Q1 2026	REGN Regeneron Pharmaceuticals, Inc.	Regeneron Pharmaceuticals, Inc.	Sell	-35,130	-21.2%	$100.95M	130,662
Q1 2026	RYN Rayonier Inc. REIT	Rayonier Inc. REIT	Buy	+5,083,702	+89.5%	$221.93M	10,762,643
Q1 2026	SAM Boston Beer Company, Inc. (The)	Boston Beer Company, Inc. (The)	Sell	-29,596	-20.0%	$27.28M	118,401
Q1 2026	SN SharkNinja	SharkNinja	Sell	-38,600	-13.3%	$26.55M	250,666
Q1 2026	TRIP TripAdvisor, Inc.	TripAdvisor, Inc.	Buy	+1,759,811	+62.0%	$49.02M	4,598,068
Q1 2026	XPO XPO, Inc.	XPO, Inc.	Sell	-6,676	-51.3%	$1.23M	6,336