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American Century increased AMPH position by 376,751 shares

Mar 28, 2026Last updated Jul 9, 2026

This StonkWhisper whale intelligence report documents significant institutional position changes in $AMPH 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.

AMERICAN CENTURY COMPANIES INC AUM: $194.3B INCREASED

AUM: $194.3B · 2,830 holdings · Period: 2025-12-31

+376,751 Share Change

665,336 Current Shares

$17.8B Current Value

0.01% Portfolio %

+130.6% Change %

Position Change Detail

Issuer AMPHASTAR PHARMACEUTICALS IN

Ticker AMPH

Shares 288,585 → 665,336 +376,751

Value $7.7B → $17.8B

Portfolio Weight 0.01%

Change Type Increased

Period of Report 2025-12-31

Other American Century Positions This Period

Ticker	Issuer	Change Type	Share Change	Value
KOS	KOSMOS ENERGY LTD	Decreased	19,075,012	$10.3B
NFLX	NETFLIX INC	Increased	+15,804,792	$1642.0B
KVUE	KENVUE INC	Decreased	10,309,137	$461.2B
T	AT&T INC	Decreased	6,329,511	$98.5B
FNB	F N B CORP	Decreased	5,985,954	$42.8B
GFL	GFL ENVIRONMENTAL INC	Decreased	5,025,075	$42.9B
VICI	VICI PPTYS INC	Decreased	4,649,026	$68.4B
MARA	MARA HOLDINGS INC	Decreased	4,372,799	$2.2B
UAA	UNDER ARMOUR INC	Decreased	3,552,342	$2.3B
APH	AMPHENOL CORP NEW	Increased	+3,437,013	$788.3B

Other Whales Moving AMPH This Period

Manager	Change Type	Share Change
Millennium	Decreased	407,092
Arrowstreet	Increased	+167,116
Invesco	Increased	+112,308
Hotchkis & Wiley	Increased	+76,380
Balyasny	Decreased	64,385
AQR Capital	Decreased	61,592
Renaissance Tech	Decreased	42,200
LSV	Increased	+37,000
Acadian	Decreased	35,017
State Street	Increased	+31,044

View all sentiment, news, and whale activity for AMPH (AMPHASTAR PHARMACEUTICALS IN).

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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: July 09, 2026 at 06:01 UTC