KEROS THERAPEUTICS INC KROS
COM · Common Stock · CUSIP 492327101 · ISIN US4923271013
- SectorHealth care
- IndustryPharmaceutical Preparations
- HeadquartersLexington, MA
- FilingsSEC EDGAR
* Summed across managers. Shares that two managers' reports both contain – a subsidiary's holdings that its parent's report includes too, or a sub-adviser's in its client's – are counted once ($1.9m this quarter). Holder counts are more reliable. Shares outstanding: 19.8m as of 2026-07-27, from the company's own SEC filing; the percentage can still exceed 100%: lent-out shares are counted by the lender and the buyer, and some reports overlap without saying so. Implied quarter-end price ≈ $10.70. Options: 1 managers hold calls ($41.7k notional), 1 hold puts ($154.1k).
Trends to Q2 2026
Institutional holders
Managers reporting a position, each quarter
Numbers
| Quarter | Holders |
|---|---|
| Q3 2022 | 113 |
| Q4 2022 | 126 |
| Q1 2023 | 130 |
| Q2 2023 | 125 |
| Q3 2023 | 108 |
| Q4 2023 | 122 |
| Q1 2024 | 148 |
| Q2 2024 | 153 |
| Q3 2024 | 165 |
| Q4 2024 | 162 |
| Q1 2025 | 158 |
| Q2 2025 | 141 |
| Q3 2025 | 155 |
| Q4 2025 | 166 |
| Q1 2026 | 151 |
| Q2 2026 | 132 |
Buyers vs sellers
Managers adding to or starting a position, vs cutting or selling out
Numbers
| Quarter | Bought or added | Cut or sold out |
|---|---|---|
| Q3 2024 | 92 | 61 |
| Q4 2024 | 100 | 70 |
| Q1 2025 | 94 | 90 |
| Q2 2025 | 85 | 77 |
| Q3 2025 | 84 | 54 |
| Q4 2025 | 75 | 98 |
| Q1 2026 | 70 | 94 |
| Q2 2026 | 62 | 79 |
Calls vs puts
Options held, notional value, last 4 quarters. P/C = puts ÷ calls
Numbers
| Quarter | Calls | Puts | P/C |
|---|---|---|---|
| Q3 2025 | $10.1m | $7.5m | 0.74 |
| Q4 2025 | $10.4m | $4.5m | 0.43 |
| Q1 2026 | $1.4m | $3.0m | 2.22 |
| Q2 2026 | $41.7k | $154.1k | 3.69 |
Biggest buyers
| Nantahala Capital Management, LLC | Added | +1.5m |
| AQR CAPITAL MANAGEMENT LLC | Added | +561.3k |
| MACKENZIE FINANCIAL CORP | Added | +476.0k |
| BlackRock, Inc. | Added | +382.4k |
| ADAR1 Capital Management, LLC | Added | +149.5k |
| DIMENSIONAL FUND ADVISORS LP | Added | +139.2k |
| O'SHAUGHNESSY ASSET MANAGEMENT, LLC | New | +126.4k |
| MILLENNIUM MANAGEMENT LLC | Added | +78.0k |
| JANE STREET GROUP, LLC | Added | +70.8k |
| BRIDGEWAY CAPITAL MANAGEMENT, LLC | Added | +70.0k |
Biggest sellers
| ARROWSTREET CAPITAL, LIMITED PARTNERSHIP | Reduced | -357.1k |
| D. E. Shaw & Co., Inc. | Reduced | -242.1k |
| GEODE CAPITAL MANAGEMENT, LLC | Reduced | -170.6k |
| Connor, Clark & Lunn Investment Management Ltd. | Reduced | -130.0k |
| TWO SIGMA INVESTMENTS, LP | Reduced | -117.2k |
| Y-Intercept (Hong Kong) Ltd | Reduced | -116.3k |
| Qube Research & Technologies Ltd | Reduced | -116.1k |
| JACOBS LEVY EQUITY MANAGEMENT, INC | Reduced | -100.6k |
| NORTHERN TRUST CORP | Reduced | -100.3k |
| Point72 Asset Management, L.P. | Reduced | -98.6k |
Biggest calls
| SIMPLEX TRADING, LLC | Reduced | $41.7k3.9k shares |
Biggest puts
| CITADEL ADVISORS LLC | Reduced | $154.1k14.4k shares |
Options at notional value: the value of the shares the contracts control, as filers report them, not what the options cost. Not included in the holders, shares or buying above.
Major shareholders (over 5%)
Anyone who owns more than 5% of a class of the company's shares has to say so: on Schedule 13D if they may try to influence or control the company, on 13G if they're a passive investor, and update it as the stake changes. Each holder's latest filing, from 19 Dec 2024 on; percentages are of the share class, as the holder worked them out.
| Holder | Stake |
|---|---|
| BlackRock Portfolio Management LLC 13G · institution +3.4 pts · filed 2026-10-27 | 9.1% |
| BlackRock, Inc. 13G · institution -1.7 pts · filed 2026-07-29 | 8.4% |
| Nantahala Capital Management, LLC 13G · institution new · filed 2026-05-15 | 6.9% |
Fell to 5% or below in the last year: VANGUARD GROUP INC (0.0%, 2026-03-27), D. E. SHAW & CO, L.P. (3.9%, 2026-02-17), TANG CAPITAL MANAGEMENT LLC (0.0%, 2026-02-17), ExodusPoint Capital Management, LP (0.0%, 2026-02-17), Madison Avenue Partners, LP (2.7%, 2026-02-17)
Insider purchases and sales since 1 Apr 2026
Shares bought or sold by the company's own officers, directors and 10% owners, in the open market or privately, as they reported to the SEC on Form 4 (due within two business days of the trade). Grants, option exercises, shares withheld for tax and gifts aren't included.
Officers and directors buying vs selling
Number of people, by quarter (10% owners not included)
Numbers
| Quarter | Buying | Bought | Selling | Sold | Sold under a plan |
|---|---|---|---|---|---|
| Q4 2024 | 0 | — | 0 | — | — |
| Q1 2025 | 0 | — | 0 | — | — |
| Q2 2025 | 0 | — | 0 | — | — |
| Q3 2025 | 0 | — | 0 | — | — |
| Q4 2025 | 0 | — | 1 | $85.0m | — |
| Q1 2026 | 1 | $22.4k | 4 | $331.8k | — |
| Q2 2026 | 1 | $32.5k | 4 | $61.8k | $61.8k |
| Q3 2026 | 1 | $20.9k | 4 | $101.1k | $5.7k |
| Date | Insider | Trade | Value |
|---|---|---|---|
| 2026-08-18 | Cho Esther Chief Legal Officer | Sold | $46.2k4.5k shares |
| 2026-08-18 | Lerner Lorena Raquel Chief Scientific Officer | Sold | $36.7k3.6k shares |
| 2026-08-18 | Tanini Annita Corp. Controller & VP, Finance | Sold | $12.6k1.2k shares |
| 2026-08-18 | Newton Charles W. Director | Sold plan | $5.7k551 shares |
| 2026-08-17 | BIENAIME JEAN JACQUES Director | Bought plan | $10.3k1.0k shares |
| 2026-07-15 | BIENAIME JEAN JACQUES Director | Bought plan | $10.6k1.0k shares |
| 2026-06-15 | BIENAIME JEAN JACQUES Director | Bought plan | $10.2k1.0k shares |
| 2026-06-11 | Newton Charles W. Director | Sold plan | $5.5k550 shares |
| 2026-06-04 | Farzan Nima Director | Sold plan | $28.2k2.6k shares |
| 2026-06-04 | Knowles Julius Director | Sold plan | $28.2k2.6k shares |
| 2026-06-04 | Seth Alpna Director | Sold plan | $28.1k2.6k shares |
| 2026-05-15 | BIENAIME JEAN JACQUES Director | Bought plan | $10.6k1.0k shares |
| 2026-04-15 | BIENAIME JEAN JACQUES Director | Bought plan | $11.7k1.0k shares |
Their holding: how much the trade added to or took from the insider's holding (direct, or the trust or fund named). The same trade is sometimes reported by more than one insider, such as a fund and the director who represents it; totals count it once. A value is left blank where the reported price is far from the market price (usually a typo).
Holders, Q2 2026
| Manager | Shares | Change |
|---|---|---|
| Nantahala Capital Management, LLC 0.91% of their portfolio | 2.8m $30.2m | Added +1.5m |
| BlackRock, Inc. 0.00% of their portfolio | 2.8m $29.9m | Added +382.4k |
| AQR CAPITAL MANAGEMENT LLC 0.00% of their portfolio | 967.9k $10.4m | Added +561.3k |
| VANGUARD CAPITAL MANAGEMENT LLC 0.00% of their portfolio | 833.6k $8.9m | Added +2.2k |
| ORBIMED ADVISORS LLC 0.15% of their portfolio | 759.2k $8.1m | Unchanged |
| FEDERATED HERMES, INC. 0.01% of their portfolio | 700.4k $7.5m | Added +11.2k |
| VANGUARD PORTFOLIO MANAGEMENT LLC 0.00% of their portfolio | 652.6k $7.0m | Reduced -29.4k |
| MACKENZIE FINANCIAL CORP 0.01% of their portfolio | 628.4k $6.7m | Added +476.0k |
| Madison Avenue Partners, LP 0.29% of their portfolio | 626.6k $6.7m | Unchanged |
| Qube Research & Technologies Ltd 0.01% of their portfolio | 608.8k $6.5m | Reduced -116.1k |
| JACOBS LEVY EQUITY MANAGEMENT, INC 0.02% of their portfolio | 605.4k $6.5m | Reduced -100.6k |
| STATE STREET CORP 0.00% of their portfolio | 541.2k $5.8m | Reduced -20.5k |
| GEODE CAPITAL MANAGEMENT, LLC 0.00% of their portfolio | 510.8k $5.5m | Reduced -170.6k |
| DIMENSIONAL FUND ADVISORS LP 0.00% of their portfolio | 460.5k $4.9m | Added +139.2k |
| CITADEL ADVISORS LLC 0.00% of their portfolio | 396.1k $4.2m | Reduced -10.6k |
| RENAISSANCE TECHNOLOGIES LLC 0.01% of their portfolio | 359.1k $3.8m | Reduced -94.4k |
| D. E. Shaw & Co., Inc. 0.00% of their portfolio | 267.5k $2.9m | Reduced -242.1k |
| BRIDGEWAY CAPITAL MANAGEMENT, LLC 0.05% of their portfolio | 265.0k $2.8m | Added +70.0k |
| Nuveen, LLC 0.00% of their portfolio | 247.8k $2.7m | Reduced -14.3k |
| ADAR1 Capital Management, LLC 0.12% of their portfolio | 246.8k $2.6m | Added +149.5k |
| TWO SIGMA INVESTMENTS, LP 0.00% of their portfolio | 246.6k $2.6m | Reduced -117.2k |
| ARROWSTREET CAPITAL, LIMITED PARTNERSHIP 0.00% of their portfolio | 233.2k $2.5m | Reduced -357.1k |
| MILLENNIUM MANAGEMENT LLC 0.00% of their portfolio | 184.8k $2.0m | Added +78.0k |
| GOLDMAN SACHS GROUP INC 0.00% of their portfolio | 177.8k $1.9m | Reduced -46.6k |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC 0.00% of their portfolio | 158.7k $1.7m | Reduced -21.2k |
| Man Group plc 0.00% of their portfolio | 155.5k $1.7m | Reduced -83.1k |
| WELLS FARGO & COMPANY/MN 0.00% of their portfolio | 155.5k $1.7m | Added +4.4k |
| NORTHERN TRUST CORP 0.00% of their portfolio | 153.8k $1.6m | Reduced -100.3k |
| BESSEMER GROUP INC 0.00% of their portfolio | 143.9k $1.5m | Unchanged |
| Empowered Funds, LLC 0.01% of their portfolio | 142.2k $1.5m | Reduced -3.4k |
| UBS Group AG 0.00% of their portfolio | 138.0k $1.5m | Reduced -7.6k |
| VANGUARD FIDUCIARY TRUST CO 0.00% of their portfolio | 131.3k $1.4m | Added +4.0k |
| Connor, Clark & Lunn Investment Management Ltd. 0.00% of their portfolio | 127.9k $1.4m | Reduced -130.0k |
| O'SHAUGHNESSY ASSET MANAGEMENT, LLC 0.01% of their portfolio | 126.4k $1.4m | New |
| ACADIAN ASSET MANAGEMENT LLC 0.00% of their portfolio | 115.6k $1.2m | Added +50.2k |
| JANE STREET GROUP, LLC 0.00% of their portfolio | 115.3k $1.2m | Added +70.8k |
| Bank of New York Mellon Corp 0.00% of their portfolio | 103.3k $1.1m | Reduced -17.6k |
| AMERIPRISE FINANCIAL INC 0.00% of their portfolio | 101.3k $1.1m | Reduced -1.1k |
| AMERICAN CENTURY COMPANIES INC 0.00% of their portfolio | 84.7k $906.1k | Added +20.4k |
| LOS ANGELES CAPITAL MANAGEMENT LLC 0.00% of their portfolio | 84.4k $902.8k | Reduced -87.8k |
| MORGAN STANLEY 0.00% of their portfolio | 79.3k $848.4k | Reduced -44.8k |
| Invesco Ltd. 0.00% of their portfolio | 71.6k $765.7k | Reduced -16.2k |
| HSBC HOLDINGS PLC 0.00% of their portfolio | 69.9k $761.5k | Added +15.9k |
| MARTINGALE ASSET MANAGEMENT L P 0.02% of their portfolio | 67.8k $725.4k | Added +20.2k |
| PRINCIPAL FINANCIAL GROUP INC 0.00% of their portfolio | 63.8k $682.7k | Added +4.2k |
| RBF Capital, LLC 0.03% of their portfolio | 62.8k $672.0k | Unchanged |
| Russell Investments Group, Ltd. 0.00% of their portfolio | 60.9k $651.5k | Reduced -20.4k |
| XTX Topco Ltd 0.01% of their portfolio | 59.5k $637.0k | Reduced -28.8k |
| Jain Global LLC 0.01% of their portfolio | 59.2k $633.5k | New |
| PRICE T ROWE ASSOCIATES INC /MD/ 0.00% of their portfolio | 56.1k $601.0k | Added +10.2k |
| PANAGORA ASSET MANAGEMENT INC 0.00% of their portfolio | 56.0k $599.0k | Added +21.3k |
| IEQ CAPITAL, LLC 0.00% of their portfolio | 55.7k $595.7k | New |
| Rangeley Capital, LLC 0.54% of their portfolio | 54.4k $582.1k | Unchanged |
| PUBLIC EMPLOYEES RETIREMENT SYSTEM OF OHIO 0.00% of their portfolio | 50.3k $538.5k | Unchanged |
| BNP PARIBAS FINANCIAL MARKETS 0.00% of their portfolio | 49.9k $533.4k | Added +42.9k |
| BARCLAYS PLC 0.00% of their portfolio | 49.7k $531.8k | Added +26.5k |
| Y-Intercept (Hong Kong) Ltd 0.01% of their portfolio | 48.2k $515.5k | Reduced -116.3k |
| MASSACHUSETTS FINANCIAL SERVICES CO /MA/ 0.00% of their portfolio | 47.1k $504.2k | Reduced -1.9k |
| DEUTSCHE BANK AG\ 0.00% of their portfolio | 46.8k $500.8k | Reduced -4.0k |
| Susquehanna Portfolio Strategies, LLC 0.01% of their portfolio | 44.8k $479.6k | New |
| Mariner, LLC 0.00% of their portfolio | 38.9k $416.2k | Added +25.1k |
| FMR LLC 0.00% of their portfolio | 35.3k $378.0k | Added +2.7k |
| PRELUDE CAPITAL MANAGEMENT, LLC 0.03% of their portfolio | 35.0k $374.9k | Reduced -11.0k |
| MARSHALL WACE, LLP 0.00% of their portfolio | 34.6k $370.2k | New |
| ALLIANCEBERNSTEIN L.P. 0.00% of their portfolio | 33.2k $366.5k | Added +2.3k |
| RHUMBLINE ADVISERS 0.00% of their portfolio | 32.8k $350.5k | Reduced -7.4k |
| BANK OF AMERICA CORP /DE/ 0.00% of their portfolio | 31.2k $334.2k | Reduced -22.4k |
| Squarepoint Ops LLC 0.00% of their portfolio | 31.2k $333.9k | New |
| MERCER GLOBAL ADVISORS INC /ADV 0.00% of their portfolio | 27.7k $296.2k | Added +15.9k |
| Quantinno Capital Management LP 0.00% of their portfolio | 27.0k $288.6k | Added +3.2k |
| CANADA PENSION PLAN INVESTMENT BOARD 0.00% of their portfolio | 23.1k $247.2k | Reduced -21.0k |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP 0.00% of their portfolio | 21.0k $225.2k | Added +9.8k |
| Cerity Partners LLC 0.00% of their portfolio | 18.3k $195.8k | New |
| WEALTH ENHANCEMENT ADVISORY SERVICES, LLC 0.00% of their portfolio | 17.8k $210.5k | New |
| Creative Planning 0.00% of their portfolio | 16.7k $178.8k | Reduced -1.1k |
| MetLife Investment Management, LLC 0.00% of their portfolio | 16.7k $178.5k | Unchanged |
| Jump Financial, LLC 0.00% of their portfolio | 15.4k $164.8k | Reduced -35.0k |
| EJF Capital LP 0.11% of their portfolio | 15.0k $160.5k | Unchanged |
| JPMORGAN CHASE & CO 0.00% of their portfolio | 14.6k $159.8k | Reduced -23.1k |
| nVerses Capital, LLC 0.22% of their portfolio | 13.1k $140.4k | New |
| Engineers Gate Manager LP 0.00% of their portfolio | 12.2k $130.7k | Reduced -4.4k |
| PDT Partners, LLC 0.01% of their portfolio | 11.4k $122.0k | Reduced -21.3k |
| Point72 Asset Management, L.P. 0.00% of their portfolio | 10.4k $111.2k | Reduced -98.6k |
| AMERICAN FINANCIAL GROUP INC 0.04% of their portfolio | 10.1k $108.1k | Unchanged |
| Arax Advisory Partners 0.00% of their portfolio | 10.0k $107.5k | Added +9.7k |
| NEW YORK STATE COMMON RETIREMENT FUND 0.00% of their portfolio | 9.1k $97.5k | Unchanged |
| CITIGROUP INC 0.00% of their portfolio | 9.0k $96.5k | Added +6.8k |
| MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd. 0.00% of their portfolio | 8.5k $91.1k | Reduced -5.4k |
| Legal & General Group Plc 0.00% of their portfolio | 8.4k $90.0k | Added +5.8k |
| Vanguard Global Advisers, LLC 0.00% of their portfolio | 7.9k $85.0k | Reduced -7.8k |
| Police & Firemen's Retirement System of New Jersey 0.00% of their portfolio | 7.7k $82.4k | Unchanged |
| NISA INVESTMENT ADVISORS, LLC 0.00% of their portfolio | 4.0k $42.7k | Added +1.8k |
| ROYAL BANK OF CANADA 0.00% of their portfolio | 3.2k $34.0k | Reduced -1.7k |
| China Universal Asset Management Co., Ltd. 0.00% of their portfolio | 3.1k $33.7k | Reduced -2.3k |
| IFP Advisors, Inc 0.00% of their portfolio | 3.0k $32.2k | Added +161 |
| Ameritas Investment Partners, Inc. 0.00% of their portfolio | 2.4k $25.4k | Unchanged |
| OSAIC HOLDINGS, INC. 0.00% of their portfolio | 2.1k $22.0k | Added +1 |
| Tower Research Capital LLC (TRC) 0.00% of their portfolio | 2.0k $21.0k | Reduced -732 |
| Integrated Wealth Concepts LLC 0.00% of their portfolio | 1.6k $17.0k | New |
| Zurcher Kantonalbank (Zurich Cantonalbank) 0.00% of their portfolio | 1.4k $15.1k | Added +716 |