Kalaris Therapeutics, Inc. (KLRS) Ownership
KLRS ownership summary
as of October 18, 2026- Institutions
- 75.8% of shares outstanding
- Insiders
- 8.81% of shares outstanding
- Shares outstanding
- 23.8M
- Float
- 7.3M shares available to trade
- Short interest
- 3.98% 332K shares short
- Days to cover
- 4.93 short interest up 4.2% vs prior month
- Institutions 75.84%
- Insiders 8.81%
- Other investors 15.35%
KLRS top institutional holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | Samsara BioCapital, LLC | 54.11% | 12.9M | $25.8M | −66,906 (−0.5%) | June 30, 2026 |
| 2 | RTW INVESTMENTS, LLC | 5.46% | 1.3M | $2.6M | — | June 30, 2026 |
| 3 | Alyeska Investment Group, L.P. | 2.41% | 573K | $1.1M | — | June 30, 2026 |
| 4 | Siren, L.L.C. | 1.83% | 436K | $871,596 | — | June 30, 2026 |
| 5 | Vanguard Capital Management, LLC | 1.67% | 399K | $797,424 | +143,364 (+56.1%) | June 30, 2026 |
| 6 | Ikarian Capital, LLC | 1.51% | 360K | $720,000 | — | June 30, 2026 |
| 7 | UBS Group AG | 1.10% | 262K | $524,262 | +255,947 (+4,138.9%) | June 30, 2026 |
| 8 | Renaissance Technologies Corp | 0.63% | 149K | $298,702 | +83,200 (+125.8%) | June 30, 2026 |
| 9 | Marshall Wace Asset Management Ltd | 0.58% | 139K | $278,402 | +71,322 (+105.1%) | June 30, 2026 |
| 10 | Geode Capital Management, LLC | 0.48% | 114K | $228,074 | +26,492 (+30.3%) | June 30, 2026 |
| 11 | Woodline Partners LP | 0.42% | 100K | $200,000 | — | June 30, 2026 |
| 12 | ADAR1 Capital Management LLC | 0.42% | 100K | $200,000 | — | June 30, 2026 |
| 13 | WHI TRUST Co LLC | 0.41% | 97K | $194,986 | — | June 30, 2026 |
| 14 | Citadel Advisors Llc | 0.40% | 96K | $191,544 | +95,772 (0.0%) | June 30, 2026 |
| 15 | BOOTHBAY FUND MANAGEMENT, LLC | 0.39% | 92K | $184,522 | — | June 30, 2026 |
| 16 | Verdad Advisers, LP | 0.34% | 80K | $160,594 | +80,297 (0.0%) | June 30, 2026 |
| 17 | Morgan Stanley - Brokerage Accounts | 0.30% | 72K | $144,652 | +33,982 (+88.6%) | June 30, 2026 |
| 18 | Vanguard Fiduciary Trust Co | 0.28% | 66K | $132,358 | +29,462 (+80.2%) | June 30, 2026 |
| 19 | BlackRock Inc | 0.23% | 54K | $108,884 | +18,399 (+51.0%) | June 30, 2026 |
| 20 | 683 Capital Management LLC | 0.19% | 45K | $90,000 | −35,590 (−44.2%) | March 31, 2026 |
Value at the latest close. Change = shares bought or sold in the latest quarterly filing (13F). In the top 20, 10 holders added 838K shares and 2 cut 102K.
KLRS top mutual fund and ETF holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | Vanguard MStar Total Stk Mkt Idx Invest | 1.07% | 255K | $510,674 | — | August 31, 2026 |
| 2 | Fidelity Extended Market Index | 0.25% | 59K | $117,130 | −315 (−0.5%) | August 31, 2026 |
| 3 | Nationwide Bailard Sm Cp Val M | 0.14% | 34K | $67,800 | +27,400 (+421.5%) | August 31, 2026 |
| 4 | iShares Micro-Cap ETF | 0.12% | 29K | $57,994 | −200 (−0.7%) | September 30, 2026 |
| 5 | EA Bridgeway Ultra-Small Company Mkt ETF | 0.09% | 22K | $45,000 | — | September 30, 2026 |
| 6 | Fidelity Series Total Market Index | 0.08% | 18K | $35,896 | +4,280 (+31.3%) | August 31, 2026 |
| 7 | Fidelity Total Market Index | 0.07% | 17K | $34,686 | +3,424 (+24.6%) | August 31, 2026 |
| 8 | Goldman Sachs Absolute Ret Trckr Instl | 0.03% | 8,020 | $16,040 | −934 (−10.4%) | June 30, 2026 |
| 9 | Fidelity VIP Disciplined Small Cap Init | 0.03% | 7,806 | $15,612 | — | July 31, 2026 |
| 10 | Vanguard Balanced Index Inv | 0.03% | 6,002 | $12,004 | — | August 31, 2026 |
| 11 | Dimensional US Core Equity 1 ETF | 0.01% | 3,296 | $6,592 | — | September 24, 2026 |
| 12 | DFA US Vector Equity I | 0.01% | 2,750 | $5,500 | — | August 31, 2026 |
| 13 | Dimensional US Core Equity 2 ETF | 0.01% | 2,614 | $5,228 | — | September 30, 2026 |
| 14 | DFA US Core Equity Class F | 0.01% | 1,943 | $3,886 | — | July 31, 2026 |
| 15 | 1290 VT Micro Cap K | 0.01% | 1,725 | $3,450 | — | August 31, 2026 |
| 16 | Victory Extended Market Index | <0.01% | 911 | $1,822 | +911 (0.0%) | June 30, 2026 |
| 17 | Vanguard U.S. Eq Idx £ Acc | <0.01% | 725 | $1,450 | — | August 31, 2026 |
| 18 | Dimensional Global Core Equity USD Acc | <0.01% | 640 | $1,280 | — | August 31, 2026 |
| 19 | JHVIT Total Stock Market Index I | <0.01% | 541 | $1,082 | +541 (0.0%) | August 31, 2026 |
| 20 | Dimensional International Core Eq Acc | <0.01% | 290 | $580 | — | August 31, 2026 |
Funds report holdings monthly or quarterly; dates differ by fund.
KLRS insider transactions
latest 2| Date | Name | Transaction | Price | Shares | Value |
|---|---|---|---|---|---|
| 2026-03-20 | Brett R Hagen | Sell | $6.72 | 1,915 | $12,869 |
| 2025-12-18 | Srinivas Akkaraju | Buy | $10.42 | 479,847 | $5.0M |
Reported trades by company officers, directors and other filers (including disclosures by members of Congress where EODHD lists them). "—" where the filing gives no share count.
KLRS shares outstanding
Year-end shares outstanding, adjusted for splits.
Who owns KLRS
Institutional investors own 75.8% of Kalaris Therapeutics's shares and insiders 8.81%. The largest holder is Samsara BioCapital, LLC with 54.11% of the shares (12.9M), as of June 30, 2026. Among the top 20 institutions, 10 added shares and 2 reduced their stake in the latest filings. Short interest is 3.98% of the float, or 4.93 days of average trading volume. The share count rose 709.1% since 2019.
Related: KLRS analyst forecast, KLRS key metrics. See the KLRS stock overview for the latest quote and news.
KLRS ownership FAQ
Who owns the most Kalaris Therapeutics stock?
The largest shareholders of Kalaris Therapeutics are Samsara BioCapital, LLC (54.11%), RTW INVESTMENTS, LLC (5.46%), Alyeska Investment Group, L.P. (2.41%), Siren, L.L.C. (1.83%), Vanguard Capital Management, LLC (1.67%).
What percentage of Kalaris Therapeutics is owned by institutions?
Institutions hold 75.8% of Kalaris Therapeutics's shares outstanding; insiders hold 8.81%.
Which funds own Kalaris Therapeutics?
The largest fund holders of Kalaris Therapeutics are Vanguard MStar Total Stk Mkt Idx Invest (1.07%), Fidelity Extended Market Index (0.25%), Nationwide Bailard Sm Cp Val M (0.14%), iShares Micro-Cap ETF (0.12%), EA Bridgeway Ultra-Small Company Mkt ETF (0.09%).
What is Kalaris Therapeutics's short interest?
332K shares of Kalaris Therapeutics were sold short, 3.98% of the float; at the average daily volume it would take 4.93 days to cover.
Are insiders buying or selling Kalaris Therapeutics?
Of the latest 2 reported insider transactions in Kalaris Therapeutics (since December 18, 2025), 1 were purchases and 1 were sales.
How many shares of Kalaris Therapeutics are outstanding?
Kalaris Therapeutics has 23.8M shares outstanding, of which 7.3M are in the public float.