Kalaris Therapeutics, Inc. (KLRS) Institutional Ownership

Institutions by Trading Activity

Ownership Statistics

0Shares Outstanding

11,581,774Shares held by institutions

$60,920,131Value of institutional holdings

71.76%Institutional ownership %

-19.62%Shares Changed QoQ

30No. of institutional investors

Shares Owned by Institutions

Shares Purchased/Sold by Institutions

Ownership Summary

Kalaris Therapeutics, Inc. (NASDAQ:KLRS) has 51 institutional investors with active 13F positions as of December 2025.

Their combined ownership stood at 96.9% of outstanding shares in December 2025, up from 70.7% in September 2025.
Their total shares held in KLRS increased 41.74% from the prior quarter, while the number of investors in Kalaris Therapeutics stayed flat year over year.
Of these 51 holders, 35 added to their stakes in Kalaris Therapeutics, 8 trimmed positions, and 8 made no changes.
In total, institutional investors held 18.11Mn shares in Kalaris Therapeutics as of December 2025, up by 5.33Mn shares quarter on quarter, and with no net change year over year.
As of December 31, 2025, Samsara BioCapital, LLC held the largest stake in Kalaris Therapeutics with 12.95Mn shares, accounting for 69.23% of total shares outstanding.
Top purchasers of KLRS stock for the quarter ending December 2025 included Samsara BioCapital, LLC (1.5Mn), RTW INVESTMENTS, LP (1.3Mn), Paradigm Biocapital Advisors LP (700.0K), Alyeska Investment Group, L.P. (403.55K), Ikarian Capital, LLC (360.0K).
The largest sales of KLRS for the quarter ending December 2025 came from Woodline Partners LP (141.1K), RENAISSANCE TECHNOLOGIES LLC (25.0K), Squarepoint Ops LLC (14.81K), UBS Group AG (2.56K), BlackRock, Inc. (1.92K).
According to Business Quant data, leading holders of KLRS for December 2025 are Samsara BioCapital, LLC (12.95Mn), RTW INVESTMENTS, LP (1.3Mn), Paradigm Biocapital Advisors LP (700.0K), Siren, L.L.C. (435.8K), Alyeska Investment Group, L.P. (403.55K), Ikarian Capital, LLC (360.0K), VANGUARD GROUP INC (292.79K), ADAR1 Capital Management, LLC (200.0K), Kalehua Capital Management LLC (139.9K), Woodline Partners LP (100.0K).

51 Institutional Holders

11,581,774 Total Shares Held

Rows:

Download Data

Owner Name	Date	Change (QoQ)	Change (%)	Value (USD)
BlackRock, Inc.	31 Dec, 2025	-1,925	-4.77%	$0.00
RTW INVESTMENTS, LP	31 Dec, 2025	1,300,000	0.00%	$0.00
Samsara BioCapital, LLC	31 Dec, 2025	1,500,000	13.10%	$0.00
Barclays Plc	31 Dec, 2025	6,065	0.00%	$0.00
Alyeska Investment Group, L.P.	31 Dec, 2025	403,551	0.00%	$0.00
Paradigm Biocapital Advisors LP	31 Dec, 2025	700,000	0.00%	$0.00
VANGUARD GROUP INC	31 Dec, 2025	89,739	44.20%	$0.00
Siren, L.L.C.	31 Dec, 2025	117,534	36.93%	$0.00
BOOTHBAY FUND MANAGEMENT, LLC	31 Dec, 2025	92,261	0.00%	$0.00
Ikarian Capital, LLC	31 Dec, 2025	360,000	0.00%	$0.00
Raymond James Financial Inc	31 Dec, 2025	88,436	0.00%	$0.00
ADAR1 Capital Management, LLC	31 Dec, 2025	200,000	0.00%	$0.00
RENAISSANCE TECHNOLOGIES LLC	31 Dec, 2025	-25,000	-22.17%	$0.00
Kalehua Capital Management LLC	31 Dec, 2025	139,901	0.00%	$0.00
Redmile Group, LLC	31 Dec, 2025	0	0.00%	$0.00
Woodline Partners LP	31 Dec, 2025	-141,102	-58.52%	$0.00
GEODE CAPITAL MANAGEMENT, LLC	31 Dec, 2025	18,096	28.03%	$0.00
WHI TRUST Co LLC	31 Dec, 2025	97,493	0.00%	$0.00
683 Capital Management, LLC	31 Dec, 2025	80,590	0.00%	$0.00
Propel Bio Management, LLC	31 Dec, 2025	42,053	0.00%	$0.00

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