H2O America HTO Insider Ownership

NASDAQ HTO

$55.88 -1.81 (-3.14%)

At close: Oct 19, 2026 · 4:00 PM EDT

Insider Holdings by Owner

9.57Mn Shares

Insider Ownership Statistics

as of 30 Sep, 2026

Insider Ownership

11.71%

▲+0.0039% pp QoQ

Shares Held by Insiders

4.90Mn

filed for Sep 2026

▲+0.03% QoQ

Shares Outstanding

41.85Mn

41,852,853 shares

Direct Holdings

4.88Mn

Indirect: 15.24K

Net Shares Traded (QoQ)

+1.61K

net buying in Sep 2026

Insiders Holding Shares

with Form 4 holdings on file

Shares Owned by Insiders

Shares held % of outstanding

Latest —

Average ownership —

Peak ownership —

Shares Purchased/Sold by Insiders

Bought Sold

Latest quarter —

Net over range —

Buying quarters —

Insider Ownership Summary

Updated Oct 5, 2026

Over the past 12 months, H2O America insiders bought $5.06 million of stock on the open market (86.3K shares) and sold $284,105 (5.22K shares).

Counted by insider, open-market buying of HTO stock in the past 12 months came from one insider and selling from 2 insiders.
Among H2O America's insiders, the largest open-market purchases in the past 12 months were by Atlas Infrastructure Partners (UK) Ltd. (10% owner), totaling $5.06 million (86.3K shares), most recently on July 7, 2026.
On the selling side, Atlas Infrastructure Partners (UK) Ltd. (10% owner) was the top open-market seller of H2O America over the past 12 months, with $184,943 sold (3.12K shares) and the latest sale on July 1, 2026.
Beyond open-market trades, insiders at H2O America received 22.18K shares in stock awards, gave up 7.34K shares to cover taxes or exercise prices and gave away 3.51K shares as gifts in the last 12 months.
Per Business Quant, HTO insiders together hold 4.9Mn shares based on their latest Form 4 filings, or 11.71% of the 41.85Mn shares outstanding; that total is up 0.03% from 4.9Mn shares at the end of Q2 2026.
Direct holdings account for 4.88Mn shares (99.69%) of HTO's insider total, and indirect holdings through trusts, partnerships and family members for 15.24K shares (0.31%).
Holdings in H2O America stock are reported by 20 insiders, the officers, directors and 10% owners who have filed a Form 4 in the past two years.
HTO's three largest insider shareholders, per their latest Form 4 filings, are Atlas Infrastructure Partners (UK) Ltd. (10% owner, 4.62Mn shares), Eric W. Thornburg (President & CEO, 78.42K shares) and Andrew F. Walters (Chief Executive Officer, 26.56K shares).
Atlas Infrastructure Partners (UK) Ltd. alone accounts for 94.19% of the shares held by H2O America insiders.
In the past year, 16 insiders of H2O America submitted 33 Form 4 filings reporting trades, awards or other transactions.
These insider figures for H2O America are based on Form 4 filings through August 3, 2026.

Form 4 Holdings

Insiders Holding HTO

Insiders 27

Shares held 9.57Mn

Of outstanding 22.87%

#	Insider	Position	Direct	Total	Share of Insiders	Last Filed
1	Infrastructure Partners (Uk) Ltd. Atlas	TenPercentOwner	4,615,265	4,615,265	48.2%	13 Jul, 2026
2	Atlas Holdings Ltd Gip	TenPercentOwner	4,582,469	4,582,469	47.9%	22 Apr, 2026
3	Eric W Thornburg	President Ceo	78,418	78,418	0.8%	04 Mar, 2025
4	Maureen P Westbrook	President Of Ctws	40,590	40,590	0.4%	30 Dec, 2022
5	Andrew F Walters	Chief Executive Officer	26,461	26,461	0.3%	06 Jul, 2026
6	Andrew Gere	President Of Sjwc	25,410	25,410	0.3%	02 Mar, 2023
7	James Patrick Lynch	Chief Accounting Officer	25,249	25,249	0.3%	04 Nov, 2022
8	Bruce A Hauk	President And Coo	16,616	16,616	0.2%	03 Mar, 2026
9	A Kristen Johnson	Chief Administrative Officer	14,565	14,565	0.2%	03 Mar, 2026
10	Megan Mattern	Cao, Pao And Controller	13,631	13,631	0.1%	03 Aug, 2026
11	Willie D. Jr. Brown	Vp Gen Counsel	13,554	13,554	0.1%	03 Mar, 2026
12	Tanya Moniz-Witten	President, San Jose Water Co.	12,812	12,812	0.1%	01 May, 2025
13	Gregory P Landis	Director	12,803	12,803	0.1%	15 May, 2025
14	Mary Ann Hanley	Director	11,583	11,583	0.1%	15 May, 2026
15	Carol P Wallace	Director	11,238	11,238	0.1%	15 May, 2026
16	Hunt Heather	Director	11,238	11,238	0.1%	15 May, 2026
17	Ann P Kelly	Cfo And Treasurer	9,976	9,976	0.1%	06 Jul, 2026
18	Rebecca A Klein	Director	9,208	9,208	0.1%	15 May, 2026
19	Carl Guardino	Director	9,139	9,139	0.1%	15 May, 2026
20	Denise L Kruger	Director	6,923	6,923	0.1%	15 May, 2026
21	Wendy Avila-Walker	Vp Of Finance, Controller	5,806	5,806	0.1%	06 Jan, 2022
22	Walter J. Bishop	Director	5,353	5,353	0.1%	29 Apr, 2022
23	Craig J Patla	President Of Ctws	5,200	5,200	0.1%	04 Mar, 2025
24	Mohammed G. Zerhouni	Svp Of Fin., Prin. Acct. Ofcr.	3,567	3,567	0.0%	05 Feb, 2024
25	Nick Orlando Rowe	Director	2,452	2,452	0.0%	15 May, 2026
26	Daniel B. More	Director	1,947	1,947	0.0%	15 May, 2026
27	Douwe Busschops	Chief Information Officer	1,768	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.

Form 4 Filings

1,443 Insider Transactions

Source SEC Form 4

Latest quarter Sep 2026

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

Showing 1 to 20 of 1,443 transactions