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Longleaf Partners decreased AVTR position by 1,143,628 shares

Mar 28, 2026Last updated Apr 16, 2026

This StonkWhisper whale intelligence report documents significant institutional position changes in $AVTR based on SEC 13F filings and block-level trading data. Quarterly 13F disclosures are required for institutional investment managers with at least $100 million in qualifying assets under management. These filings reveal long positions in U.S. equities held as of quarter end. Material changes in institutional positioning — particularly from concentrated funds with a history of high-conviction bets — are tracked by StonkWhisper as leading indicators of institutional thesis formation or exit.

SOUTHEASTERN ASSET MANAGEMENT INC/TN/ AUM: $2.2B DECREASED

AUM: $2.2B · 92 holdings · Period: 2025-12-31

1,143,628 Share Change

3,086,436 Current Shares

$35.4B Current Value

1.58% Portfolio %

-27.0% Change %

Position Change Detail

Issuer AVANTOR INC

Ticker AVTR

Shares 4,230,064 → 3,086,436 1,143,628

Value $52.8B → $35.4B

Portfolio Weight 1.58%

Change Type Decreased

Period of Report 2025-12-31

Other Longleaf Partners Positions This Period

Ticker	Issuer	Change Type	Share Change	Value
ACI	ALBERTSONS COS INC	Increased	+1,222,843	$90.9B
RYN	RAYONIER INC	Increased	+1,147,193	$110.2B
0J7Q	IAC INC	Increased	+1,080,300	$130.6B
ESRT	EMPIRE ST RLTY TR INC	Increased	+1,072,638	$24.1B
PCH	POTLATCHDELTIC CORPORATION	Increased	+955,591	$112.5B
TRIP	TRIPADVISOR INC	Increased	+492,788	$41.3B
SHEN	SHENANDOAH TELECOMMUNICATION	Increased	+491,652	$33.9B
CLW	CLEARWATER PAPER CORP	Increased	+442,386	$24.0B
HTHT	H WORLD GROUP LTD	Decreased	356,629	$10.9B
LPX	LOUISIANA PAC CORP	New	+231,095	$18.7B

Other Whales Moving AVTR This Period

Manager	Change Type	Share Change
Engine Capital	Decreased	7,792,618
Invesco	Decreased	4,347,082
DE Shaw	Increased	+3,994,579
Point72	Exited	2,495,068
Tudor	Increased	+1,795,200
Renaissance Tech	Exited	1,651,100
American Century	Exited	1,524,991
Millennium	Increased	+966,487
Gotham Asset	Decreased	685,178
BlackRock	Decreased	683,604

View all sentiment, news, and whale activity for AVTR (AVANTOR INC).

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Data sourced from SEC 13F institutional holdings filings. This page does not constitute financial advice. StonkWhisper presents public records — it does not verify or guarantee the accuracy of institutional filings. 13F filings are reported quarterly and may lag actual positions.

Last updated: April 16, 2026 at 06:01 UTC