SEC Insider Transactions from SPRINGER TIMOTHY A.

Last updated: 2026-03-14 11:44 UTC | Total transactions: 111

Timothy A. Springer made 13 open market purchases of Cartesian Therapeutics ($RNAC) shares totaling about $2.9 million over the last year, with the latest on April 11, 2025; these rank 250th among nearly 5,000 insiders averaging $1.5 million across 3.3 buys. He also bought Tectonic Therapeutic ($TECX) shares 10 times for about $10.8 million, ranking 99th, most recently on April 11, 2025. Springer reported no open market sales in the past 365 days.

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Transaction Date Company Ticker Insider Name Title Transaction Type Security Shares Price Shares Owned Following Total Shares Outstanding % of Owned % of Outstanding
Jan. 2, 2026 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director A Common Stock 2600 $0.00 9,633,493.0000 26,003,606 0.03% 0.01%
Jan. 2, 2026 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director A Stock Option (Right to Buy) 7800 $0.00 7,800.0000 26,003,606 9999.99% 0.03%
June 9, 2025 Tectonic Therapeutic, Inc. $TECX SPRINGER TIMOTHY A Not found A Stock Option (Right to Buy) 10200 $0.00 10,200.0000 18,662,672 9999.99% 0.05%
April 10, 2025 Tectonic Therapeutic, Inc. $TECX SPRINGER TIMOTHY A Not found P Common Stock 8092 $16.73 6,014,860.0000 18,662,672 0.13% 0.04%
April 11, 2025 Tectonic Therapeutic, Inc. $TECX SPRINGER TIMOTHY A Not found P Common Stock 9478 $16.31 6,024,338.0000 18,662,672 0.16% 0.05%
April 9, 2025 Tectonic Therapeutic, Inc. $TECX SPRINGER TIMOTHY A Not found P Common Stock 16215 $14.62 5,919,918.0000 18,662,672 0.27% 0.09%
April 9, 2025 Tectonic Therapeutic, Inc. $TECX SPRINGER TIMOTHY A Not found P Common Stock 4856 $15.23 5,924,774.0000 18,662,672 0.08% 0.03%
April 10, 2025 Tectonic Therapeutic, Inc. $TECX SPRINGER TIMOTHY A Not found P Common Stock 45858 $16.73 5,970,632.0000 18,662,672 0.77% 0.25%
April 11, 2025 Tectonic Therapeutic, Inc. $TECX SPRINGER TIMOTHY A Not found P Common Stock 53706 $16.31 6,024,338.0000 18,662,672 0.90% 0.29%
April 9, 2025 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 178 $9.95 9,545,960.0000 25,936,101 0.00% 0.00%
April 9, 2025 Tectonic Therapeutic, Inc. $TECX SPRINGER TIMOTHY A Not found P Common Stock 2861 $14.62 6,005,911.0000 18,662,672 0.05% 0.02%
April 9, 2025 Tectonic Therapeutic, Inc. $TECX SPRINGER TIMOTHY A Not found P Common Stock 857 $15.23 6,006,768.0000 18,662,672 0.01% 0.00%
April 10, 2025 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 3451 $10.92 9,594,555.0000 25,936,101 0.04% 0.01%
April 10, 2025 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 45144 $10.43 9,591,104.0000 25,936,101 0.47% 0.17%
April 10, 2025 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 609 $10.92 9,624,481.0000 25,936,101 0.01% 0.00%
April 9, 2025 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 7342 $9.43 9,615,875.0000 25,936,101 0.08% 0.03%
April 9, 2025 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 31 $9.95 9,615,906.0000 25,936,101 0.00% 0.00%
April 9, 2025 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 41604 $9.43 9,545,782.0000 25,936,101 0.44% 0.16%
April 10, 2025 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 7966 $10.43 9,623,872.0000 25,936,101 0.08% 0.03%
April 11, 2025 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 36338 $10.77 9,630,893.0000 25,936,101 0.38% 0.14%
April 11, 2025 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 6412 $10.77 9,630,893.0000 25,936,101 0.07% 0.02%
April 7, 2025 Tectonic Therapeutic, Inc. $TECX SPRINGER TIMOTHY A Not found P Common Stock 412500 $17.10 5,882,415.0000 18,662,672 7.54% 2.21%
April 7, 2025 Tectonic Therapeutic, Inc. $TECX SPRINGER TIMOTHY A Not found P Common Stock 87500 $17.10 5,882,415.0000 18,662,672 1.51% 0.47%
March 18, 2025 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 14740 $14.42 9,406,695.0000 25,767,369 0.16% 0.06%
March 19, 2025 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 20234 $14.97 9,426,929.0000 25,767,369 0.22% 0.08%
March 20, 2025 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 54889 $15.59 9,481,818.0000 25,767,369 0.58% 0.21%
Feb. 5, 2025 Tectonic Therapeutic, Inc. $TECX SPRINGER TIMOTHY A Not found P Common Stock 129294 $54.14 5,382,415.0000 0 2.46% 0.00%
Feb. 5, 2025 Tectonic Therapeutic, Inc. $TECX SPRINGER TIMOTHY A Not found P Common Stock 660000 $50.00 5,382,415.0000 0 13.98% 0.00%
Jan. 13, 2025 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 8983 $17.78 9,387,933.0000 25,767,369 0.10% 0.03%
Jan. 13, 2025 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 7962 $16.86 9,378,950.0000 25,767,369 0.08% 0.03%
Jan. 14, 2025 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 4022 $18.00 9,391,955.0000 25,767,369 0.04% 0.02%
Jan. 2, 2025 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director A Common Stock 2600 $0.00 9,370,988.0000 25,767,369 0.03% 0.01%
Jan. 2, 2025 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director A Stock Option (Right to Buy) 7800 $0.00 7,800.0000 25,767,369 9999.99% 0.03%
Dec. 23, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 5181 $19.00 9,368,388.0000 23,896,525 0.06% 0.02%
Dec. 19, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 11303 $17.39 9,327,502.0000 23,896,525 0.12% 0.05%
Dec. 19, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 3376 $18.93 9,341,407.0000 23,896,525 0.04% 0.01%
Dec. 19, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 10529 $18.35 9,338,031.0000 23,896,525 0.11% 0.04%
Dec. 20, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 21800 $18.94 9,363,207.0000 23,896,525 0.23% 0.09%
Nov. 14, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 22242 $16.97 8,980,658.0000 23,896,525 0.25% 0.09%
Nov. 14, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 74157 $16.19 8,958,416.0000 23,896,525 0.83% 0.31%
Nov. 18, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 38114 $17.96 9,296,018.0000 23,896,525 0.41% 0.16%
Nov. 18, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 20181 $18.42 9,316,199.0000 23,896,525 0.22% 0.08%
Nov. 15, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 277246 $17.09 9,257,904.0000 23,896,525 3.09% 1.16%
Oct. 22, 2024 Tectonic Therapeutic, Inc. $TECX SPRINGER TIMOTHY A Not found P Common Stock 300000 $33.59 4,593,121.0000 0 6.99% 0.00%
Oct. 2, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director J Common Stock 317879 $0.00 8,884,259.0000 23,896,525 3.71% 1.33%
Oct. 2, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director J Common Stock 1801314 $0.00 8,678,538.0000 23,896,525 26.19% 7.54%
Oct. 2, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 5514 $17.38 8,684,052.0000 23,896,525 0.06% 0.02%
Oct. 2, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director J Common Stock 2119193 $0.00 8,884,259.0000 23,896,525 19.26% 8.87%
Oct. 3, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 29847 $18.25 8,713,899.0000 23,896,525 0.34% 0.12%
Oct. 3, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 10249 $19.01 8,724,148.0000 23,896,525 0.12% 0.04%
Oct. 3, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 50489 $20.18 8,774,637.0000 23,896,525 0.58% 0.21%
Oct. 3, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 21278 $21.17 8,795,915.0000 23,896,525 0.24% 0.09%
Oct. 3, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 8043 $21.86 8,803,958.0000 23,896,525 0.09% 0.03%
Oct. 4, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 9892 $21.35 8,813,850.0000 23,896,525 0.11% 0.04%
Oct. 4, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 48880 $22.35 8,862,730.0000 23,896,525 0.55% 0.20%
Oct. 4, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 16650 $23.57 8,879,380.0000 23,896,525 0.19% 0.07%
Oct. 4, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 4879 $23.93 8,884,259.0000 23,896,525 0.05% 0.02%
Oct. 2, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director J Warrant (Right to Buy) 133632 $0.00 167,040.0000 23,896,525 44.44% 0.56%
Oct. 2, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director J Warrant (Right to Buy) 113587 $0.00 167,040.0000 23,896,525 212.50% 0.48%
Oct. 2, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director J Warrant (Right to Buy) 20045 $0.00 167,040.0000 23,896,525 13.64% 0.08%
Sept. 25, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director M Common Stock 1636832 $0.00 8,678,538.0000 17,816,238 23.24% 9.19%
Sept. 25, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director M Common Stock 1307 $0.00 8,678,538.0000 17,816,238 0.02% 0.01%
Sept. 25, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director M Series B Non-Voting Convertible Preferred Stock 1307 $0.00 0.0000 17,816,238 100.00% 0.01%
Sept. 25, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director M Common Stock 721361 $0.00 8,678,538.0000 17,816,238 9.07% 4.05%
Sept. 25, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director M Series B Non-Voting Convertible Preferred Stock 721361 $0.00 0.0000 17,816,238 100.00% 4.05%
Sept. 25, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director M Series B Non-Voting Convertible Preferred Stock 1636832 $0.00 0.0000 17,816,238 100.00% 9.19%
Sept. 26, 2024 Tectonic Therapeutic, Inc. $TECX SPRINGER TIMOTHY A Not found P Common Stock 24531 $28.16 4,267,652.0000 0 0.58% 0.00%
Sept. 26, 2024 Tectonic Therapeutic, Inc. $TECX SPRINGER TIMOTHY A Not found P Common Stock 4070 $30.10 4,290,721.0000 0 0.09% 0.00%
Sept. 26, 2024 Tectonic Therapeutic, Inc. $TECX SPRINGER TIMOTHY A Not found P Common Stock 2400 $30.87 4,293,121.0000 0 0.06% 0.00%
Sept. 24, 2024 Tectonic Therapeutic, Inc. $TECX SPRINGER TIMOTHY A Not found J Common Stock 1054759 $0.00 4,243,121.0000 0 33.08% 0.00%
Sept. 24, 2024 Tectonic Therapeutic, Inc. $TECX SPRINGER TIMOTHY A Not found J Common Stock 1240893 $0.00 4,293,121.0000 0 22.42% 0.00%
Sept. 24, 2024 Tectonic Therapeutic, Inc. $TECX SPRINGER TIMOTHY A Not found J Common Stock 186134 $0.00 4,293,121.0000 0 4.53% 0.00%
Sept. 26, 2024 Tectonic Therapeutic, Inc. $TECX SPRINGER TIMOTHY A Not found P Common Stock 18999 $29.13 4,286,651.0000 0 0.45% 0.00%
Aug. 12, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 8016 $12.72 6,319,038.0000 17,816,238 0.13% 0.04%
July 2, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director A Series B Non-Voting Convertible Preferred Stock 1307 $20.00 2,359,500.0000 17,816,238 0.06% 0.01%
July 2, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director A Series B Non-Voting Convertible Preferred Stock 1636832 $20.00 2,359,500.0000 17,816,238 226.50% 9.19%
July 2, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director A Series B Non-Voting Convertible Preferred Stock 721361 $20.00 2,359,500.0000 17,816,238 44.04% 4.05%
June 20, 2024 Tectonic Therapeutic, Inc. $TECX SPRINGER TIMOTHY A Not found A Common Stock 2692005 $0.00 4,243,121.0000 0 173.55% 0.00%
June 20, 2024 Tectonic Therapeutic, Inc. $TECX SPRINGER TIMOTHY A Not found A Stock Option (Right to Buy) 11760 $0.00 11,760.0000 0 9999.99% 0.00%
June 20, 2024 Tectonic Therapeutic, Inc. $TECX SPRINGER TIMOTHY A Not found A Common Stock 1551116 $0.00 4,243,121.0000 0 57.62% 0.00%
April 8, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director M Series A Non-Voting Convertible Preferred Stock 24785 $0.00 0.0000 5,515,836 100.00% 0.45%
April 8, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director M Common Stock 826169 $0.00 6,311,022.0000 5,515,836 15.06% 14.98%
April 8, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director M Series A Non-Voting Convertible Preferred Stock 123925 $0.00 0.0000 5,515,836 100.00% 2.25%
April 8, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director M Common Stock 4130846 $0.00 6,311,022.0000 5,515,836 189.47% 74.89%
March 18, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 800 $0.61 40,620,292.0000 5,397,597 0.00% 0.01%
Jan. 17, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 800 $0.69 40,602,692.0000 5,397,597 0.00% 0.01%
Feb. 6, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 800 $0.65 40,603,492.0000 5,397,597 0.00% 0.01%
Feb. 7, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 2400 $0.66 40,605,892.0000 5,397,597 0.01% 0.04%
March 8, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 4800 $0.66 40,610,692.0000 5,397,597 0.01% 0.09%
March 11, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 1200 $0.65 40,611,892.0000 5,397,597 0.00% 0.02%
March 12, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 1200 $0.61 40,613,092.0000 5,397,597 0.00% 0.02%
March 13, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 3200 $0.58 40,616,292.0000 5,397,597 0.01% 0.06%
March 14, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 2000 $0.53 40,618,292.0000 5,397,597 0.00% 0.04%
March 15, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 1200 $0.56 40,619,492.0000 5,397,597 0.00% 0.02%
March 26, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director M Warrant (Right to Buy) 1970443 $0.00 0.0000 5,397,597 100.00% 36.51%
March 26, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director M Common Stock 1970443 $1.46 40,601,892.0000 5,397,597 5.10% 36.51%
March 18, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 19044 $0.60 38,631,449.0000 5,397,597 0.05% 0.35%
March 15, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 537500 $0.59 38,612,405.0000 5,397,597 1.41% 9.96%
March 14, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director P Common Stock 648372 $0.54 38,074,905.0000 5,397,597 1.73% 12.01%
Jan. 2, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director A Stock Option (Right to Buy) 228000 $0.00 228,000.0000 5,397,597 9999.99% 4.22%
Jan. 2, 2024 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director A Common Stock 178000 $0.00 37,426,533.0000 5,397,597 0.48% 3.30%
Nov. 15, 2023 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director A Series A Convertible Preferred Stock 123925 $403.47 148,710.4880 5,101,459 500.00% 2.43%
Nov. 13, 2023 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director D Stock Option (Right to Buy) 6410 $0.00 0.0000 5,101,459 100.00% 0.13%
Nov. 13, 2023 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director D Stock Option (Right to Buy) 10000 $0.00 0.0000 5,101,459 100.00% 0.20%
Nov. 13, 2023 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director D Stock Option (Right to Buy) 10000 $0.00 0.0000 5,101,459 100.00% 0.20%
Nov. 13, 2023 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director D Stock Option (Right to Buy) 75000 $0.93 0.0000 5,101,459 100.00% 1.47%
Nov. 13, 2023 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director D Stock Option (Right to Buy) 40000 $0.00 0.0000 5,101,459 100.00% 0.78%
Nov. 13, 2023 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director D Stock Option (Right to Buy) 40000 $0.00 0.0000 5,101,459 100.00% 0.78%
Nov. 13, 2023 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director D Stock Option (Right to Buy) 20000 $0.00 0.0000 5,101,459 100.00% 0.39%
Nov. 15, 2023 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director A Series A Convertible Preferred Stock 24785 $403.47 148,710.4880 5,101,459 20.00% 0.49%
Jan. 2, 2023 Cartesian Therapeutics, Inc. $RNAC SPRINGER TIMOTHY A Director A Stock Option (Right to Buy) 75000 $0.00 75,000.0000 5,101,459 9999.99% 1.47%