As of September 29, 2026, the three largest insider holders of ERII are Arve Hanstveit (Director, 400.60K shares), Robert Yu Lang Mao (President And Ceo, 248.94K shares), David W Moon (President And Ceo, 233.07K shares).
| # | Insider | Position | Direct | Indirect | Total | Share of Insiders | Last Filed |
|---|---|---|---|---|---|---|---|
| 1 | Arve Hanstveit | Director | 400,603 | 0 | 400,603 | 23.2% | 05 Jun, 2026 |
| 2 | Robert Yu Lang Mao | President And Ceo | 248,935 | 0 | 248,935 | 14.4% | 24 May, 2024 |
| 3 | David W Moon | President And Ceo | 233,069 | 0 | 233,069 | 13.5% | 19 Feb, 2026 |
| 4 | Farshad Ghasripoor | Chief Technology Officer | 52,860 | 70,230 | 123,090 | 7.1% | 05 Feb, 2025 |
| 5 | Rodney Clemente | Svp, Water | 108,301 | 0 | 108,301 | 6.3% | 29 Jul, 2026 |
| 6 | William Yeung | Chief Legal Officer | 99,291 | 0 | 99,291 | 5.7% | 29 Jul, 2026 |
| 7 | Michael S. Mancini | Chief Financial Officer | 75,051 | 0 | 75,051 | 4.3% | 19 Feb, 2026 |
| 8 | Alexander J Buehler | Interim President And Ceo | 66,755 | 0 | 66,755 | 3.9% | 17 Jun, 2026 |
| 9 | Pamela L. Tondreau | Director | 60,844 | 0 | 60,844 | 3.5% | 05 Jun, 2026 |
| 10 | Colin R Sabol | Director | 55,671 | 0 | 55,671 | 3.2% | 17 Jun, 2026 |
| 11 | Natarajan Ramanan | Chief Technology Officer | 52,565 | 0 | 52,565 | 3.0% | 06 Mar, 2026 |
| 12 | Joan Kai Chow | Director | 52,116 | 0 | 52,116 | 3.0% | 05 Jun, 2026 |
| 13 | Matthew Hostetler | Chief Human Resources Officer | 46,556 | 0 | 46,556 | 2.7% | 19 Feb, 2026 |
| 14 | Joshua Ballard | Chief Financial Officer | 40,376 | 0 | 40,376 | 2.3% | 30 May, 2024 |
| 15 | Aidan Ryan | Interim Cfo | 34,133 | 0 | 34,133 | 2.0% | 24 Jun, 2026 |
| 16 | John Joseph Mitchell | Director | 16,797 | 0 | 16,797 | 1.0% | 21 Jul, 2026 |
| 17 | Sherif Foda | Director | 9,619 | 0 | 9,619 | 0.6% | 16 Sep, 2022 |
| 18 | Lisa A Pollina | Director | 4,007 | 0 | 4,007 | 0.2% | 13 Jun, 2023 |
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 |
|---|---|---|---|---|---|---|---|---|
| 27 Jul, 2026 | Rodney Clemente | Svp, Water | Disposed F | 2,320 | $8.42 | $19.53K | 113,688 | Direct |
| 27 Jul, 2026 | William Yeung | Chief Legal Officer | Disposed F | 2,828 | $8.42 | $23.81K | 101,339 | Direct |
| 28 Jul, 2026 | Rodney Clemente | Svp, Water | Disposed S | 5,387 | $8.56 | $46.11K | 108,301 | Direct |
| 28 Jul, 2026 | William Yeung | Chief Legal Officer | Disposed S | 2,048 | $8.56 | $17.53K | 99,291 | Direct |
| 09 Jul, 2026 | John Joseph Mitchell | Director | Acquired A | 16,797 | $0.00 | $0 | 16,797 | Direct |
| 06 May, 2026 | Aidan Ryan | Interim Cfo | Acquired A | 18,518 | $11.61 | $214.99K | 34,133 | Direct |
| 15 Jun, 2026 | Alexander J Buehler | Interim President And Ceo | Acquired M | 15,327 | $8.60 | $131.81K | 81,655 | Direct |
| 15 Jun, 2026 | Colin R Sabol | Director | Acquired P | 11,180 | $8.88 | $99.27K | 55,671 | Direct |
| 15 Jun, 2026 | Alexander J Buehler | Interim President And Ceo | Disposed S | 14,900 | $8.71 | $129.78K | 66,755 | Direct |
| 15 Jun, 2026 | Alexander J Buehler | Interim President And Ceo | Disposed M | 15,327 | $8.60 | $131.81K | 0 | Direct |
| 04 Jun, 2026 | Joan Kai Chow | Director | Acquired A | 18,094 | $8.29 | $150.00K | 52,116 | Direct |
| 04 Jun, 2026 | Pamela L. Tondreau | Director | Acquired A | 22,316 | $8.29 | $185.00K | 60,844 | Direct |
| 04 Jun, 2026 | Colin R Sabol | Director | Acquired A | 18,094 | $8.29 | $150.00K | 44,491 | Direct |
| 04 Jun, 2026 | Arve Hanstveit | Director | Acquired A | 18,094 | $8.29 | $150.00K | 400,603 | Direct |
| 13 May, 2026 | Pamela L. Tondreau | Director | Acquired P | 20,000 | $8.34 | $166.84K | 37,362 | Indirect |
| 06 Apr, 2026 | Arve Hanstveit | Director | Disposed S | 2,419 | $10.29 | $24.89K | 382,509 | Direct |
| 02 Apr, 2026 | Arve Hanstveit | Director | Disposed S | 165,292 | $10.14 | $1.68Mn | 384,928 | Direct |
| 10 Mar, 2026 | Arve Hanstveit | Director | Disposed S | 25,000 | $10.96 | $273.98K | 550,220 | Direct |
| 05 Mar, 2026 | Arve Hanstveit | Director | Disposed S | 38,418 | $10.71 | $411.46K | 586,802 | Direct |
| 06 Mar, 2026 | Arve Hanstveit | Director | Disposed S | 11,582 | $10.62 | $122.94K | 575,220 | Direct |