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SCHEDULE 13D/A Filed 2026-04-02 Event 2026-03-31 SEC 0001193125-26-140633 →

Kalayoglu Murat Cartesian Therapeutics, Inc. RNAC

Stake: 19.90% Shares: 5,833,971 CUSIP: 816212104 Class: Common Stock

Item 4 — Purpose of Transaction

Item 4 of the Schedule 13D is supplemented as follows: On March 31, 2026, Murat Kalayoglu resigned as a member of the Issuer's board of directors. On April 2, 2026, pursuant to a Notice of Optional Conversion delivered to the Issuer by the Trust pursuant to Section 6.02 of the Certificate of Designation, as amended by the Amendment to the Certificate of Designation, 22,740.030 shares of Series A Preferred Stock held by the Trust were converted into 758,001 shares of Common Stock.

Cross-References

Insider Activity (last 365d)
2 transactions
0 buys · 0 sales · 2 awards/exercises
Issuer Cluster
16 13D/G filings on this issuer
15 other filings besides this one
Filer Track Record
2 filings by this filer
1 other filing in the data moat
Short Interest · settle 2026-07-15
DTC 12.30
1,925,634 shares short · +2.1% vs prior

Institutional Consensus · 2025-12-31

Held by elite portfolio managers
1 holder · $244K
Point72 Asset Mgmt

Post-Filing Returns · since 2026-03-31 on RNAC

+1 day
+3.9%
+5 days
+1.5%
+30 days
+63.4%
+60 days
+63.4%
+90 days
+63.4%
+180 days

Anchor price 6.15 on closest trading day on/after 2026-03-31. Source: Yahoo Finance daily adj_close (split + dividend adjusted).

Form 4 Insider Transactions · last 365d

DateInsiderRoleTypeSharesPriceValue
2026-04-02 Hoge Elizabeth 10%+ owner Option exercise 758,001
2026-04-02 Kalayoglu Murat 10%+ owner Option exercise 758,001

Other 13D/G Filings on Cartesian Therapeutics, Inc.

FiledFormFilerStakeShares
2025-01-15 SCHEDULE SPRINGER TIMOTHY A 36.90% 9,555,394 view →
2024-10-15 SC Kalayoglu Murat view →
2024-07-05 SC SPRINGER TIMOTHY A view →
2024-04-12 SC SPRINGER TIMOTHY A view →
2021-12-27 SC SPRINGER TIMOTHY A view →
2021-05-27 SC SPRINGER TIMOTHY A view →
2020-10-23 SC SPRINGER TIMOTHY A view →
2020-10-15 SC SPRINGER TIMOTHY A view →
2020-02-05 SC ORBIMED ADVISORS LLC view →
2020-01-02 SC SPRINGER TIMOTHY A view →
2019-12-17 SC SPRINGER TIMOTHY A view →
2019-11-13 SC ORBIMED ADVISORS LLC view →
2019-02-04 SC Polaris Venture Partners V, L.P. view →
2018-05-03 SC Polaris Venture Partners V, L.P. view →
2018-01-26 SC ORBIMED ADVISORS LLC view →

Other Filings by Kalayoglu Murat

FiledFormIssuerStakeShares
2024-10-15 SC Cartesian Therapeutics, Inc. RNAC view →

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