As of September 29, 2026, the three largest insider holders of HTO are Infrastructure Partners (Uk) Ltd. Atlas (TenPercentOwner, 4.62Mn shares), Atlas Holdings Ltd Gip (TenPercentOwner, 4.58Mn shares), Eric W Thornburg (President Ceo, 78.42K shares).
| # | Insider | Position | Direct | Indirect | Total | Share of Insiders | Last Filed |
|---|---|---|---|---|---|---|---|
| 1 | Infrastructure Partners (Uk) Ltd. Atlas | TenPercentOwner | 4,615,265 | 0 | 4,615,265 | 48.2% | 13 Jul, 2026 |
| 2 | Atlas Holdings Ltd Gip | TenPercentOwner | 4,582,469 | 0 | 4,582,469 | 47.9% | 22 Apr, 2026 |
| 3 | Eric W Thornburg | President Ceo | 78,418 | 0 | 78,418 | 0.8% | 04 Mar, 2025 |
| 4 | Maureen P Westbrook | President Of Ctws | 40,590 | 0 | 40,590 | 0.4% | 30 Dec, 2022 |
| 5 | Andrew F Walters | Chief Executive Officer | 26,461 | 0 | 26,461 | 0.3% | 06 Jul, 2026 |
| 6 | Andrew Gere | President Of Sjwc | 25,410 | 0 | 25,410 | 0.3% | 02 Mar, 2023 |
| 7 | James Patrick Lynch | Chief Accounting Officer | 25,249 | 0 | 25,249 | 0.3% | 04 Nov, 2022 |
| 8 | Bruce A Hauk | President And Coo | 16,616 | 0 | 16,616 | 0.2% | 03 Mar, 2026 |
| 9 | A Kristen Johnson | Chief Administrative Officer | 14,565 | 0 | 14,565 | 0.2% | 03 Mar, 2026 |
| 10 | Megan Mattern | Cao, Pao And Controller | 13,631 | 0 | 13,631 | 0.1% | 03 Aug, 2026 |
| 11 | Willie D. Jr. Brown | Vp Gen Counsel | 13,554 | 0 | 13,554 | 0.1% | 03 Mar, 2026 |
| 12 | Tanya Moniz-Witten | President, San Jose Water Co. | 12,812 | 0 | 12,812 | 0.1% | 01 May, 2025 |
| 13 | Gregory P Landis | Director | 12,803 | 0 | 12,803 | 0.1% | 15 May, 2025 |
| 14 | Mary Ann Hanley | Director | 11,583 | 0 | 11,583 | 0.1% | 15 May, 2026 |
| 15 | Carol P Wallace | Director | 11,238 | 0 | 11,238 | 0.1% | 15 May, 2026 |
| 16 | Hunt Heather | Director | 11,238 | 0 | 11,238 | 0.1% | 15 May, 2026 |
| 17 | Ann P Kelly | Cfo And Treasurer | 9,976 | 0 | 9,976 | 0.1% | 06 Jul, 2026 |
| 18 | Rebecca A Klein | Director | 9,208 | 0 | 9,208 | 0.1% | 15 May, 2026 |
| 19 | Carl Guardino | Director | 9,139 | 0 | 9,139 | 0.1% | 15 May, 2026 |
| 20 | Denise L Kruger | Director | 6,923 | 0 | 6,923 | 0.1% | 15 May, 2026 |
| 21 | Wendy Avila-Walker | Vp Of Finance, Controller | 5,806 | 0 | 5,806 | 0.1% | 06 Jan, 2022 |
| 22 | Walter J. Bishop | Director | 5,353 | 0 | 5,353 | 0.1% | 29 Apr, 2022 |
| 23 | Craig J Patla | President Of Ctws | 5,200 | 0 | 5,200 | 0.1% | 04 Mar, 2025 |
| 24 | Mohammed G. Zerhouni | Svp Of Fin., Prin. Acct. Ofcr. | 3,567 | 0 | 3,567 | 0.0% | 05 Feb, 2024 |
| 25 | Katharine Armstrong | Director | 0 | 2,700 | 2,700 | 0.0% | 09 Dec, 2021 |
| 26 | Nick Orlando Rowe | Director | 2,452 | 0 | 2,452 | 0.0% | 15 May, 2026 |
| 27 | Daniel B. More | Director | 1,947 | 0 | 1,947 | 0.0% | 15 May, 2026 |
| 28 | Douwe Busschops | Chief Information Officer | 1,768 | 0 | 1,768 | 0.0% | 06 Jan, 2025 |
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 |
|---|---|---|---|---|---|---|---|---|
| 30 Jul, 2026 | Megan Mattern | Cao, Pao And Controller | Disposed F | 1,154 | $61.97 | $71.51K | 13,631 | Direct |
| 07 Jul, 2026 | Infrastructure Partners (Uk) Ltd. Atlas | TenPercentOwner | Acquired P | 2,784 | $62.03 | $172.69K | 4,615,265 | Direct |
| 07 Jul, 2026 | Infrastructure Partners (Uk) Ltd. Atlas | TenPercentOwner | Acquired P | 2,784 | $62.03 | $172.69K | 4,615,265 | Direct |
| 01 Jul, 2026 | Andrew F Walters | Chief Executive Officer | Disposed D | 374 | $60.74 | $22.72K | 26,461 | Direct |
| 01 Jul, 2026 | Ann P Kelly | Cfo And Treasurer | Disposed F | 88 | $60.74 | $5.35K | 9,976 | Direct |
| 01 Jul, 2026 | Infrastructure Partners (Uk) Ltd. Atlas | TenPercentOwner | Disposed S | 1,686 | $60.74 | $102.40K | 4,610,349 | Direct |
| 01 Jul, 2026 | Infrastructure Partners (Uk) Ltd. Atlas | TenPercentOwner | Acquired P | 2,132 | $60.76 | $129.53K | 4,612,481 | Direct |
| 05 Jun, 2026 | Andrew F Walters | Chief Executive Officer | Disposed G | 3,508 | $0.00 | $0 | 26,835 | Direct |
| 29 May, 2026 | Infrastructure Partners (Uk) Ltd. Atlas | TenPercentOwner | Disposed S | 1,435 | $57.52 | $82.54K | 4,581,034 | Direct |
| 29 May, 2026 | Infrastructure Partners (Uk) Ltd. Atlas | TenPercentOwner | Acquired P | 31,001 | $57.62 | $1.79Mn | 4,612,035 | Direct |
| 13 May, 2026 | Rebecca A Klein | Director | Acquired A | 1,947 | $0.00 | $0 | 9,208 | Direct |
| 13 May, 2026 | Nick Orlando Rowe | Director | Acquired A | 1,947 | $0.00 | $0 | 2,452 | Direct |
| 13 May, 2026 | Daniel B. More | Director | Acquired A | 1,947 | $0.00 | $0 | 1,947 | Direct |
| 13 May, 2026 | Mary Ann Hanley | Director | Acquired A | 1,947 | $0.00 | $0 | 11,583 | Direct |
| 13 May, 2026 | Carl Guardino | Director | Acquired A | 1,947 | $0.00 | $0 | 9,139 | Direct |
| 13 May, 2026 | Denise L Kruger | Director | Acquired A | 1,947 | $0.00 | $0 | 6,923 | Direct |
| 13 May, 2026 | Carol P Wallace | Director | Acquired A | 1,947 | $0.00 | $0 | 11,238 | Direct |
| 13 May, 2026 | Hunt Heather | Director | Acquired A | 1,947 | $0.00 | $0 | 11,238 | Direct |
| 10 Apr, 2026 | Atlas Holdings Ltd Gip | TenPercentOwner | Acquired P | 50,385 | $59.06 | $2.98Mn | 4,582,469 | Direct |
| 10 Apr, 2026 | Infrastructure Partners (Uk) Ltd. Atlas | TenPercentOwner | Acquired P | 50,385 | $59.06 | $2.98Mn | 4,582,469 | Direct |