Johannes Jacob Pieter Kastelein

Companies

• NewAmsterdam Pharma Co N.V.Board member Dec 29, 2023 to now¹
• NewAmsterdam Pharma Co N.V.Chief Scientific Officer Dec 29, 2023 to now¹

Holdings

Stock this person has reported owning, from the forms officers and directors file with the SEC. See the biggest insider stakes.

Shares held

• NPNewAmsterdam Pharma Co N.V. NAMS122,802 shares²$2.5M at $20.29Aug 25, 2026

As of each latest filing. The line shows shares held over time.

Recent filings

• Aug 24, 2026Sold 125,000 shares at $26.91 of NewAmsterdam Pharma Co N.V.²
• Aug 24, 2026Exercised options 125,000 shares of NewAmsterdam Pharma Co N.V.²
• Mar 9, 2026Sold 101,409 shares at $30.29 of NewAmsterdam Pharma Co N.V.³
• Mar 9, 2026Exercised options 101,409 shares of NewAmsterdam Pharma Co N.V.³
• Mar 6, 2026Sold 94,124 shares at $30.32 of NewAmsterdam Pharma Co N.V.³
• Mar 6, 2026Exercised options 94,124 shares of NewAmsterdam Pharma Co N.V.³
• Mar 5, 2026Sold 104,467 shares at $30.30 of NewAmsterdam Pharma Co N.V.³
• Mar 5, 2026Exercised options 104,467 shares of NewAmsterdam Pharma Co N.V.³
• Feb 20, 2026Sold 30,789 shares at $35.46 of NewAmsterdam Pharma Co N.V.⁴
• Feb 20, 2026Sold 14,692 shares at $35.00 of NewAmsterdam Pharma Co N.V.⁴
• Jan 7, 2026Granted 25,500 shares of NewAmsterdam Pharma Co N.V.⁵
• Jan 5, 2026Sold 6,000 shares at $33.25 of NewAmsterdam Pharma Co N.V.⁵
• Aug 22, 2025Sold 7,658 shares at $25.49 of NewAmsterdam Pharma Co N.V.⁶
• Aug 22, 2025Sold 42,342 shares at $25.08 of NewAmsterdam Pharma Co N.V.⁶
• Aug 21, 2025Sold 50,000 shares at $24.29 of NewAmsterdam Pharma Co N.V.⁶
• Mar 26, 2025Exercised options 45,481 shares of NewAmsterdam Pharma Co N.V.⁷
• Mar 26, 2025Granted 19,302 shares of NewAmsterdam Pharma Co N.V.⁷
• Mar 24, 2025Exercised options 150,000 shares of NewAmsterdam Pharma Co N.V.⁸
• Jan 7, 2025Granted 34,000 shares of NewAmsterdam Pharma Co N.V.⁹
• Mar 26, 2024Sold 190,476 shares at $21.50 of NewAmsterdam Pharma Co N.V.¹⁰
• Mar 26, 2024Shares withheld for tax 11,197 shares at $22.72 of NewAmsterdam Pharma Co N.V.¹⁰
• Mar 26, 2024Exercised options 201,673 shares of NewAmsterdam Pharma Co N.V.¹⁰