63% buyers of institutions opening or closing positions this quarter
6 more new buyers than exits, ownership fell 26.58 percentage points vs the prior quarter, and 1 well-known fund manager in the top 25.
63% buyers of institutions opening or closing positions this quarter
129.3% institutional ownership
Samsara BioCapital, LLC portfolio allocation
Institutional ownership vs Biotechnology peers
No Form 4 insider transactions on file
Latest positioning in KLRS across 13F flow, ownership shift, marquee holders, and holder-count growth.
Ranked by reported Q1 2026 13F market value
Share of total reported institutional value in KLRS held by the largest 10 / 25 filers.
| # | Institution | Shares Held | Market Value | QoQ Change | Ownership % | % of Fund |
|---|---|---|---|---|---|---|
| 1 | Samsara BioCapital, LLC | 12.9M | $74.7M | 0.0% | 69.231% | 7.26% |
| 2 | RTW INVESTMENTS, LP | 1.3M | $7.5M | 0.0% | 6.951% | 0.07% |
| 3 | Paradigm Biocapital Advisors LP | 700K | $4.0M | 0.0% | 3.743% | 0.08% |
| 4 | Alyeska Investment Group, L.P. | 573K | $3.3M | +41.9% | 3.062% | 0.01% |
| 5 | Siren, L.L.C. | 436K | $2.5M | 0.0% | 2.330% | 0.07% |
| 6 | Ikarian Capital, LLC | 360K | $2.1M | 0.0% | 1.925% | 0.17% |
| 7 | Propel Bio Management, LLC | 296K | $1.7M | +603.3% | 1.581% | 1.08% |
| 8 | VANGUARD CAPITAL MANAGEMENT LLC | 255K | $1.5M | — | 1.365% | 0.00% |
| 9 | Kalehua Capital Management LLC | 136K | $782K | -3.1% | 0.725% | 0.66% |
| 10 | RAYMOND JAMES FINANCIAL INC | 119K | $686K | +34.4% | 0.636% | 0.00% |
| 11 | GOLDMAN SACHS GROUP INC | 111K | $638K | +222.1% | 0.591% | 0.00% |
| 12 | ADAR1 Capital Management, LLC | 100K | $577K | 0.0% | 0.535% | 0.03% |
| 13 | Woodline Partners LP | 100K | $577K | 0.0% | 0.535% | 0.00% |
| 14 | WHI TRUST Co LLC | 97K | $563K | 0.0% | 0.521% | 0.42% |
| 15 | BOOTHBAY FUND MANAGEMENT, LLC | 92K | $532K | 0.0% | 0.493% | 0.01% |
| 16 | GEODE CAPITAL MANAGEMENT, LLC | 88K | $505K | +5.9% | 0.468% | 0.00% |
| 17 | Simplify Asset Management Inc. | 87K | $504K | +335.5% | 0.468% | 0.01% |
| 18 | MARSHALL WACE, LLP | 68K | $392K | -6.9% | 0.363% | 0.00% |
| 19 | RENAISSANCE TECHNOLOGIES LLC | 66K | $382K | -24.6% | 0.354% | 0.00% |
| 20 | MILLENNIUM MANAGEMENT LLC | 60K | $344K | — | 0.318% | 0.00% |
| 21 | SUSQUEHANNA INTERNATIONAL GROUP, LLP | 53K | $304K | +309.8% | 0.282% | 0.00% |
| 22 | 683 Capital Management, LLC | 45K | $260K | -44.2% | 0.241% | 0.01% |
| 23 | Fortis Capital Advisors, LLC | 40K | $231K | 0.0% | 0.214% | 0.03% |
| 24 | Belpointe Asset Management LLC | 40K | $231K | 0.0% | 0.214% | 0.01% |
| 25 | Squarepoint Ops LLC | 40K | $229K | +56.8% | 0.213% | 0.00% |
denotes a marquee investor (Buffett, Burry, ARK, Tiger Global, Pershing Square, Baupost and other widely-followed managers). “% of Fund” shows how much of that investor’s total 13F portfolio is invested in KLRS — a direct measure of their conviction.
Filings activity in KLRS during Q1 2026, grouped by how each filer changed its position.
5 quarters of 13F filings · Δ columns show change vs prior quarter
| Quarter | Inst. Holders | Δ Holders | Ownership % | Δ Ownership | Total 13F Value | Δ Value |
|---|---|---|---|---|---|---|
| Q1 2026 | 57 | +12% | 129.29% | 26.58 pp | $107M | 29% |
| Q4 2025 | 51 | +59% | 155.87% | +77.43 pp | $152M | +99% |
| Q3 2025 | 32 | +3.2% | 78.44% | +41.83 pp | $76M | +114% |
| Q2 2025 | 31 | 6.1% | 36.61% | 113.17 pp | $36M | 71% |
| Q1 2025 | 33 | — | 149.78% | — | $124M | — |
Source: SEC 13F institutional filings. Ownership % requires market cap data and will show once linked. Δ columns compare to the immediately prior filed quarter.
No recent Form 4 insider transactions on file for KLRS.
Quick answers to the most common questions about buying KLRS stock.
Based on Q1 2026 13F filings, institutional ownership of Kalaris Therapeutics Inc stands at 129.3%, held across 57 reporting institutions.
Samsara BioCapital, LLC is the largest reported institutional holder of KLRS, with approximately 12,948,081 shares worth $0.07B as of Q1 2026.
Yes — 1 widely-followed marquee investor appear among the top 25 institutional holders of KLRS, including RENAISSANCE TECHNOLOGIES LLC.
Our composite Smart Money Score for KLRS is 43 out of 100 (Neutral). It combines net institutional buying activity, ownership shift, marquee investor presence, and holder-count growth.
15 institutions opened new positions in KLRS during Q1 2026, while 9 fully exited. 8 added to existing positions and 33 trimmed.
KLRS institutional ownership fell by 26.58 percentage points quarter-over-quarter, with a net change of +6 holders.
The top 10 institutions account for 92.2% of all reported 13F value in KLRS, and the top 25 account for 98.1%.
All data is sourced from SEC Form 13F filings, which institutional investment managers with at least $100M in assets are required to file each quarter. We process every 13F filing from EDGAR and recompute the aggregates after each cycle. Insider transactions are sourced from Form 4 filings.