Comparable stake leader
Timothy A. Springer
SEC ownership of Cartesian Therapeutics, Inc.
Top holders, 13D/G large-stake signals, insider positions, and transaction flow tied to CIK 0001453687.
Disclosed value leader
Timothy A. Springer
Comparable rows
50/50
Latest evidence
31 Mar 2026
- Public ticker
- RNAC on Nasdaq
- Parsed ownership sources
-
13D/G, 3/4/5, and 13F
Source: Parsed SEC ownership filingsUse: Compare filing families carefully
- Largest SEC-reported holder
-
Timothy A. Springer
Ranking: Comparable ownership first, then disclosed value
- Comparable ownership rows
-
50 of 50
Meaning: Rows with safely comparable ownership %
- Latest 13D/G holder
-
Timothy A. Springer
Source: Latest parsed Schedule 13D/G stake
- Latest parsed ownership date
-
31 Mar 2026
Freshness: Most recent filing date in this holder set
- Issuer CIK
- 0001453687
- Issuer location
- Frederick, MD
Ownership snapshot
CIK-linked ownership evidence from parsed SEC filings.
3 signals
Issuer
Names, identifiers, and filing context for this profile.
2 identity fields
Ownership snapshot
Top shareholders of Cartesian Therapeutics, Inc. (13F + 13D/G + 3/4/5)
Grouped by holder across the latest SEC ownership disclosures. Start with comparable ownership when available, then verify the linked 13F, 13D/G, or 3/4/5 evidence.
Comparable stake leader
Timothy A. Springer
Disclosed value leader
Timothy A. Springer
Comparable rows
50/50
Latest evidence
31 Mar 2026
13D/G
3/4/5
13F
Lead comparable stake: 37%
13D/G row: Timothy A. Springer
Showing 1-8 of 50 holder rows.
Quick read
Timothy A. Springer leads the comparable SEC ownership view at 37%.
50 of 50 rows have a safely comparable ownership percentage. Use this as a filing-backed starting point, then open the detailed table for source links, reporting role, position value, share count, and filing date.
Open SEC evidence
Opens Timothy A. Springer's linked filing trail.
Comparable ownership
Top 5
Timothy A. Springer
37%
Murat Kalayoglu
20%
Squarepoint Ops LLC
8.3%
JPMORGAN CHASE & CO
6.1%
FMR LLC
3%
Ownership % is shown only when SEC disclosures are safely comparable across share classes.
Detailed SEC evidence table Showing 1-8 of 50 holder rows
| Holder | Evidence | Ownership % | Position | 12M Net Δ | As of |
|---|---|---|---|---|---|
| Timothy A. Springer |
13D/G
3/4/5
Director, 10%+ Owner
|
37%
|
$116,671,361
9,555,394 shares
|
+$258,583 | 13 Jan 2025 |
| Murat Kalayoglu |
13D/G
3/4/5
10%+ Owner
|
20%
|
$48,188,600
5,833,971 shares
|
$0 | 31 Mar 2026 |
| Squarepoint Ops LLC |
13D/G
13F
Company
|
8.3%
|
$14,163,542
2,209,601 shares
|
$0 | 09 Mar 2026 |
| JPMORGAN CHASE & CO |
13D/G
13F
Company
|
6.1%
|
$20,459,516
1,675,636 shares
|
$0 | 31 Mar 2025 |
| FMR LLC |
13D/G
13F
Company
|
3%
|
$4,990,396
799,743 shares
|
-$3,539,615 | 31 Mar 2026 |
| BlackRock, Inc. |
13F
Company
|
2.2%
|
$3,684,515
599,108 shares
|
— | 31 Mar 2026 |
| VANGUARD CAPITAL MANAGEMENT LLC |
13F
Company
|
1.5%
|
$2,506,722
407,597 shares
|
— | 31 Mar 2026 |
| 683 Capital Management, LLC |
13F
Company
|
1.2%
|
$2,029,500
330,000 shares
|
— | 31 Mar 2026 |
How to read this table
Rows are grouped by holder and ranked first by SEC-reported ownership % when it is safely comparable, then by disclosed holdings value. — indicates unavailable or non-comparable values; "mixed-class rows" means the latest filing spans non-comparable classes.
Forms 3/4/5 flow
Insider trading overview
Net insider flow leans to selling over the last 12 months. Net value: -$52,874.
Buys
$205,797
Insiders: 1
Sells
$258,671
Insiders: 3
Net
-$52,874
Shares: -7,930
Window
Last 12 months
4 rolling buckets
Buy value
Sell value
Shares: 30,000
Shares: 37,930
| Window (months) | Buy shares | Sell shares | Buy value | Sell value | Net value |
|---|---|---|---|---|---|
| 0-3 | 0 | 0 | $0 | $0 | $0 |
| 3-6 | 0 | 37,930 | $0 | $258,671 | -$258,671 |
| 6-9 | 30,000 | 0 | $205,797 | $0 | +$205,797 |
| 9-12 | 0 | 0 | $0 | $0 | $0 |
Reporting owners
Insider holders from Forms 3/4/5
Showing 1-20 of 26 reporting-owner rows connected to Cartesian Therapeutics, Inc.. Open a relationship link for the CIK-to-CIK filing trail.
Rows
26
Largest Forms 3/4/5 holder
Timothy A. Springer
Net 12M change
-$52,874
Latest report
02 Apr 2026
| Name | Relationship | Holdings Value | Past Year Net Change | Change % | Valuation | Report Date |
|---|---|---|---|---|---|---|
| Timothy A. Springer | Director, 10%+ Owner | $81,409,176 | Mixed | 02 Jan 2026 | ||
| Murat Kalayoglu | 10%+ Owner | $41,970,235 | Mixed | 02 Apr 2026 | ||
| Seven One Eight Three Four Irrevocable Trust | 10%+ Owner | $41,964,073 | Mixed | 02 Apr 2026 | ||
| Elizabeth Hoge | 10%+ Owner | $41,964,073 | Mixed | 02 Apr 2026 | ||
| Carsten Brunn | President and CEO, Director | $2,206,377 | -$162,077 | -6.8% | Filing P/S | 06 Jan 2026 |
| Metin Kurtoglu | Chief Technology Officer | $1,110,427 | Mixed | 03 Jan 2025 | ||
| Michael Singer | Director | $1,081,194 | Mixed | 13 Mar 2026 | ||
| Peter G. Traber | Chief Medical Officer | $930,762 | Mixed | 25 Sep 2023 | ||
| Lloyd P. Johnston | Chief Operations Officer | $922,211 | Mixed | 04 Jan 2023 | ||
| Emily English | Chief Operations Officer | $835,211 | Mixed | 02 Jan 2026 | ||
| Blaine Davis | Chief Financial Officer | $826,684 | -$72,227 | -8% | Filing P/S | 06 Jan 2026 |
| Aymeric Sallin | Director | $546,800 | Mixed | 02 Jan 2024 | ||
| Timothy C. Barabe | Director | $487,524 | +$205,797 | +73% | Mixed | 02 Jan 2026 |
| Takashi Kei Kishimoto | Chief Scientific Officer | $464,151 | Mixed | 30 May 2023 | ||
| Kevin Tan | Chief Financial Officer | $427,220 | Mixed | 03 Jan 2022 | ||
| Milos Miljkovic | Chief Medical Officer | $401,134 | -$24,367 | -5.7% | Filing P/S | 06 Jan 2026 |
| Christopher M. Jewell | Chief Scientific Officer | $255,114 | Mixed | 10 Jan 2025 | ||
| ZENNER PATRICK J | Director | $115,792 | Mixed | 02 Jan 2026 | ||
| Nishan M. DeSilva | Director | $102,204 | Mixed | 02 Jan 2026 | ||
| Kemal Malik | Director | $100,235 | Mixed | 02 Jan 2026 |
Recent insider transactions for Cartesian Therapeutics, Inc.
Showing up to 300 recent insider transactions from the last 12 months.
| Insider | Symbol | Class | Transaction | % | SEC-reported value | SEC-reported price | Shares | Shares owned | Date | Ownership |
|---|---|---|---|---|---|---|---|---|---|---|
| Hoge Elizabeth | RNAC | Common Stock | Options Exercise | 16.6% | 758,001 | 5,313,261 | 02 Apr 2026 | as trustee | ||
| Elizabeth Hoge | RNAC | Common Stock | Options Exercise | 16.6% | 758,001 | 5,313,261 | 02 Apr 2026 | as trustee | ||
| Hoge Elizabeth | RNAC | Series A Non-Voting Convertible Preferred Stock | Options Exercise | -40.3% | -22,740 | 33,662 | 02 Apr 2026 | as trustee | ||
| Elizabeth Hoge | RNAC | Series A Non-Voting Convertible Preferred Stock | Options Exercise | -40.3% | -22,740 | 33,662 | 02 Apr 2026 | as trustee | ||
| Murat Kalayoglu | RNAC | Common Stock | Options Exercise | 16.6% | 758,001 | 5,313,261 | 02 Apr 2026 | by trust | ||
| Murat Kalayoglu | RNAC | Series A Non-Voting Convertible Preferred Stock | Options Exercise | -40.3% | -22,740 | 33,662 | 02 Apr 2026 | by trust | ||
| Michael Singer | RNAC | Common Stock | Gift | -11.7% | -6,555 | 49,578 | 13 Mar 2026 | Direct | ||
| Carsten Brunn | RNAC | Common Stock | Sale | -6.84% | $162,077 | $6.82 | -23,766 | 323,530 | 06 Jan 2026 | Direct |
| Milos Miljkovic | RNAC | Common Stock | Sale | -5.73% | $24,367 | $6.82 | -3,573 | 58,820 | 06 Jan 2026 | Direct |
| Blaine Davis | RNAC | Common Stock | Sale | -8.03% | $72,227 | $6.82 | -10,591 | 121,220 | 06 Jan 2026 | Direct |
| Nishan M. DeSilva | RNAC | Common Stock | Award | 29.7% | 2,600 | 11,366 | 02 Jan 2026 | Direct | ||
| Nishan M. DeSilva | RNAC | Stock Option (Right to Buy) | Award | 7,800 | 7,800 | 02 Jan 2026 | Direct | |||
| Carsten Brunn | RNAC | Common Stock | Award | 70.2% | 143,200 | 347,296 | 02 Jan 2026 | Direct | ||
| Carsten Brunn | RNAC | Employee Stock Option (right to buy) | Award | 415,700 | 415,700 | 02 Jan 2026 | Direct | |||
| Kemal Malik | RNAC | Common Stock | Award | 30.5% | 2,600 | 11,133 | 02 Jan 2026 | Direct | ||
| Kemal Malik | RNAC | Stock Option (Right to Buy) | Award | 7,800 | 7,800 | 02 Jan 2026 | Direct | |||
| Milos Miljkovic | RNAC | Common Stock | Award | 76.3% | 27,000 | 62,393 | 02 Jan 2026 | Direct | ||
| Milos Miljkovic | RNAC | Employee Stock Option (right to buy) | Award | 77,000 | 77,000 | 02 Jan 2026 | Direct | |||
| Zenner Patrick J | RNAC | Common Stock | Award | 25.1% | 2,600 | 12,974 | 02 Jan 2026 | Direct | ||
| Zenner Patrick J | RNAC | Stock Option (Right to Buy) | Award | 7,800 | 7,800 | 02 Jan 2026 | Direct | |||
| June Ann Seymour | RNAC | Common Stock | Award | 6,500 | 6,500 | 02 Jan 2026 | Direct | |||
| June Ann Seymour | RNAC | Employee Stock Option (right to buy) | Award | 19,000 | 19,000 | 02 Jan 2026 | Direct | |||
| Blaine Davis | RNAC | Common Stock | Award | 39% | 37,000 | 131,811 | 02 Jan 2026 | Direct | ||
| Blaine Davis | RNAC | Employee Stock Option (right to buy) | Award | 109,000 | 109,000 | 02 Jan 2026 | Direct | |||
| Timothy C. Barabe | RNAC | Common Stock | Award | 4.78% | 2,600 | 56,966 | 02 Jan 2026 | Direct | ||
| Timothy C. Barabe | RNAC | Stock Option (Right to Buy) | Award | 7,800 | 7,800 | 02 Jan 2026 | Direct | |||
| Emily English | RNAC | Common Stock | Award | 34.2% | 24,000 | 94,226 | 02 Jan 2026 | Direct | ||
| Emily English | RNAC | Employee Stock Option (right to buy) | Award | 71,000 | 71,000 | 02 Jan 2026 | Direct | |||
| Michael Singer | RNAC | Common Stock | Award | 4.86% | 2,600 | 56,133 | 02 Jan 2026 | Direct | ||
| Michael Singer | RNAC | Stock Option (Right to Buy) | Award | 7,800 | 7,800 | 02 Jan 2026 | Direct | |||
| Timothy A. Springer | RNAC | Common Stock | Award | 0.03% | 2,600 | 8,646,285 | 02 Jan 2026 | Direct | ||
| Timothy A. Springer | RNAC | Stock Option (Right to Buy) | Award | 7,800 | 7,800 | 02 Jan 2026 | Direct | |||
| Murat Kalayoglu | RNAC | Common Stock | Award | 0.51% | 2,600 | 511,577 | 02 Jan 2026 | Direct | ||
| Murat Kalayoglu | RNAC | Stock Option (Right to Buy) | Award | 7,800 | 7,800 | 02 Jan 2026 | Direct | |||
| Emily English | RNAC | Common Stock | Options Exercise | 12% | 7,500 | 70,226 | 30 Dec 2025 | Direct | ||
| Emily English | RNAC | Stock Option (Right to Buy) | Options Exercise | -27.9% | -7,500 | 19,369 | 30 Dec 2025 | Direct | ||
| Adrian Ion Bot | RNAC | Common Stock | Award | 5,800 | 5,800 | 16 Dec 2025 | Direct | |||
| Adrian Ion Bot | RNAC | Stock Option (Right to Buy) | Award | 17,200 | 17,200 | 16 Dec 2025 | Direct | |||
| Timothy C. Barabe | RNAC | Common Stock | Purchase | 123.1% | $205,797 | $6.86 | 30,000 | 54,366 | 04 Dec 2025 | Direct |
| Emily English | RNAC | Common Stock | Options Exercise | 13.6% | 7,500 | 62,726 | 28 Nov 2025 | Direct | ||
| Emily English | RNAC | Stock Option (Right to Buy) | Options Exercise | -21.8% | -7,500 | 26,869 | 28 Nov 2025 | Direct | ||
| Michael Singer | RNAC | Common Stock | Gift | -27.2% | -20,000 | 53,533 | 18 Nov 2025 | Direct | ||
| June Ann Seymour | RNAC | Employee Stock Option (right to buy) | Award | 50,000 | 50,000 | 27 Oct 2025 | Direct |
* marks a reported price that did not pass the local price check.