As of September 29, 2026, the three largest insider holders of CSTM are Ingrid Joerg (Ceo, 406.46K shares), Ludovic Piquier (Svp Manuf Excellence Cto, 241.71K shares), Jack Q. Guo (Evp Cfo, 185.37K shares).
| # | Insider | Position | Direct | Indirect | Total | Share of Insiders | Last Filed |
|---|---|---|---|---|---|---|---|
| 1 | Ingrid Joerg | Ceo | 406,464 | 0 | 406,464 | 25.7% | 13 Jul, 2026 |
| 2 | Ludovic Piquier | Svp Manuf Excellence Cto | 241,713 | 0 | 241,713 | 15.3% | 13 May, 2026 |
| 3 | Jack Q. Guo | Evp Cfo | 185,368 | 0 | 185,368 | 11.7% | 07 May, 2026 |
| 4 | Philip Ryan Jurkovic | Svp Chro | 172,149 | 0 | 172,149 | 10.9% | 04 May, 2026 |
| 5 | Philippe Hoffmann | President, At | 144,153 | 0 | 144,153 | 9.1% | 05 May, 2026 |
| 6 | Nicolas Brun | Svp Pa, Comm Sust | 104,891 | 0 | 104,891 | 6.6% | 12 May, 2026 |
| 7 | Stephane Corre | President, Asi | 62,313 | 0 | 62,313 | 3.9% | 12 May, 2026 |
| 8 | Jean-Christophe Deslarzes | Director | 43,515 | 0 | 43,515 | 2.8% | 03 Aug, 2026 |
| 9 | Michiel Brandjes | Director | 41,600 | 0 | 41,600 | 2.6% | 07 May, 2026 |
| 10 | Niklaus Schild | Svp Cio Cdo | 38,703 | 0 | 38,703 | 2.4% | 16 Mar, 2026 |
| 11 | Matthew B. Perkins | President, Parp | 33,212 | 0 | 33,212 | 2.1% | 16 Mar, 2026 |
| 12 | Stephen Charles Walters | Svp Gc Secretary | 25,068 | 0 | 25,068 | 1.6% | 16 Mar, 2026 |
| 13 | John Ormerod | Director | 24,873 | 0 | 24,873 | 1.6% | 08 Jun, 2026 |
| 14 | Isabelle Boccon-Gibod | Director | 23,000 | 0 | 23,000 | 1.5% | 27 Feb, 2026 |
| 15 | Marcus Becker | Svp Cpo | 16,784 | 0 | 16,784 | 1.1% | 01 Jun, 2026 |
| 16 | Martin Jarrett | Svp Chief Innovation Officer | 15,375 | 0 | 15,375 | 1.0% | 18 May, 2026 |
| 17 | Bradley Lee Soultz | Director | 0 | 2,500 | 2,500 | 0.2% | 18 May, 2026 |
| 18 | Wiebke Weiler | Director | 625 | 0 | 625 | 0.0% | 16 Mar, 2026 |
Each row is that insider’s most recently reported position, from Form 4 filings over the last 60 months — which is why this total does not tie to the quarterly series above, where a quarter counts only the insiders who filed in it. Shares held through a fund or institutional portfolio are counted on the institutional ownership page instead.
| Date | Insider | Position | Transaction | Shares | Price | Value | Shares Held After | Ownership |
|---|---|---|---|---|---|---|---|---|
| 03 Aug, 2026 | Jean-Christophe Deslarzes | Director | Acquired P | 1,490 | $27.24 | $40.59K | 43,515 | Direct |
| 10 Jul, 2026 | Ingrid Joerg | Ceo | Disposed F | 2,984 | $29.28 | $87.37K | 406,464 | Direct |
| 04 Jun, 2026 | John Ormerod | Director | Disposed S | 8,000 | $35.01 | $280.08K | 24,873 | Direct |
| 28 May, 2026 | Marcus Becker | Svp Cpo | Disposed S | 10,391 | $34.93 | $362.96K | 16,784 | Direct |
| 14 May, 2026 | Bradley Lee Soultz | Director | Acquired P | 2,500 | $33.84 | $84.60K | 2,500 | Indirect |
| 14 May, 2026 | Martin Jarrett | Svp Chief Innovation Officer | Disposed S | 4,716 | $33.46 | $157.80K | 15,375 | Direct |
| 12 May, 2026 | Ludovic Piquier | Svp Manuf Excellence Cto | Disposed S | 1,000 | $33.57 | $33.57K | 241,713 | Direct |
| 11 May, 2026 | Nicolas Brun | Svp Pa, Comm Sust | Disposed S | 26,661 | $33.85 | $902.47K | 104,891 | Direct |
| 08 May, 2026 | Stephane Corre | President, Asi | Disposed S | 5,000 | $33.52 | $167.60K | 62,313 | Direct |
| 05 May, 2026 | Michiel Brandjes | Director | Disposed S | 10,400 | $31.25 | $325.00K | 41,600 | Direct |
| 05 May, 2026 | Jack Q. Guo | Evp Cfo | Disposed S | 25,201 | $32.62 | $822.06K | 185,368 | Direct |
| 01 May, 2026 | Philippe Hoffmann | President, At | Disposed S | 50,000 | $31.92 | $1.60Mn | 144,153 | Direct |
| 01 May, 2026 | Philip Ryan Jurkovic | Svp Chro | Disposed S | 48,784 | $32.01 | $1.56Mn | 172,149 | Direct |
| 01 May, 2026 | Stephane Corre | President, Asi | Disposed S | 5,000 | $32.04 | $160.20K | 67,313 | Direct |
| 01 May, 2026 | Jean-Christophe Deslarzes | Director | Acquired P | 1,325 | $31.13 | $41.25K | 42,025 | Direct |
| 16 Mar, 2026 | Marcus Becker | Svp Cpo | Disposed S | 10,000 | $25.09 | $250.90K | 27,175 | Direct |
| 02 Mar, 2026 | Jean-Christophe Deslarzes | Director | Acquired P | 1,665 | $24.77 | $41.24K | 40,700 | Direct |
| 12 Mar, 2026 | Matthew B. Perkins | President, Parp | Acquired A | 10,210 | $0.00 | $0 | 33,212 | Direct |
| 12 Mar, 2026 | Niklaus Schild | Svp Cio Cdo | Acquired A | 3,355 | $0.00 | $0 | 38,703 | Direct |
| 12 Mar, 2026 | Stephane Corre | President, Asi | Acquired A | 7,293 | $0.00 | $0 | 72,313 | Direct |