Southern Water's holding and finance companies

analysisRead together, the registers of people with significant control retrieved from Companies House in October 2026 show a line of UK companies above Southern Water Services Limited, each registered as holding 75% or more of the shares of the company below it. Going upwards, they are SWS Holdings, SWS Group Holdings, Southern Water Services Group, Southern Water Investments, Southern Water Capital, Greensands Finance, Greensands Finance Holdings, Greensands Investments, Greensands Senior Finance, Greensands Junior Finance, Sandstone Bidco, Sandstone Midco and Sandstone Water Holdings, whose sole shareholder at 28 May 2026 was the Luxembourg company MSCIF Sandstone Ventures S.à r.l. At the three Sandstone companies, Macquarie Infrastructure and Real Assets (Europe) Limited is registered alongside the shareholder as having significant influence or control. Until 4 July 2025 the line ran instead from Greensands Junior Finance to Greensands (UK) Limited and, according to the group accounts, through Greensands Europe to Greensands Holdings. This is a reading of the register entries side by side: the register of Greensands Junior Finance lists Sandstone Bidco with shares only, without voting or appointment rights, and the links between Greensands (UK), Greensands Europe and Greensands Holdings come from the accounts rather than the registers. ^{1 2 3 4}

analysisThe register for Southern Water Services Limited lists a single registrable controller, SWS Holdings Limited (company number 04324499), notified on 6 April 2016 with 75% or more of the shares and voting rights and the right to appoint or remove directors; Southern Water's annual report for the year to 31 March 2026 also names SWS Holdings as the company's immediate parent undertaking. The next two registers follow the same pattern, each listing one controller notified on 6 April 2016 with the same holdings and rights: the register for SWS Holdings lists SWS Group Holdings Limited (04324498), and the register for SWS Group Holdings lists Southern Water Services Group Limited (04374956). ^{1 2 3 4}

analysisGreensands Holdings' report for 2020–21 describes SWS Holdings as the immediate holding company of Southern Water and SWS Group Holdings as an intermediate holding company, both part of the securitised group set up in 2003, whose immediate parent is Southern Water Services Group Limited. Lenders to this financing group are secured by a charge over the share capital of SWS Group Holdings, not over Southern Water's regulated operating assets. Southern Water's annual report for the year to 31 March 2026 likewise states that the security granted to the lenders of the Southern Water Financing Group is limited to the share capital of SWS Group Holdings. ^{5 2}

analysisThe register for Southern Water Services Group lists Southern Water Investments Limited (04650294) as its only registrable controller, and the register for Southern Water Investments lists Southern Water Capital Limited (04608528); both entries were notified on 6 April 2016 with 75% or more of the shares and voting rights and the right to appoint or remove directors. The register for Southern Water (NR) Holdings Limited (04772485) also lists Southern Water Investments as its only registrable controller, on the same date and terms, so Southern Water Investments is the registered controller both of that company and of Southern Water Services Group, which sits above Southern Water Services. ^{1 2 3}

analysisSouthern Water Limited (company number 02366620) is a separate company from Southern Water Services Limited (02366670). Its register lists Southern Water (NR) Limited, a company registered in Scotland under number SC215844, as its only registrable controller, notified on 6 April 2016 with 75% or more of the shares and voting rights and the right to appoint or remove directors. Greensands Holdings' 2020–21 accounts list Southern Water Limited, Southern Water (NR) Limited and Southern Water (NR) Holdings Limited among the wholly owned subsidiaries of Greensands Europe Limited. ^{4 5 6}

analysisAbove Southern Water Capital the registers show a change in 2018. The register for Southern Water Capital lists Greensands Finance Limited (11493345) as its active registrable controller, notified on 23 October 2018, with 75% or more of the shares and voting rights and the right to appoint or remove directors; Greensands Investments Limited (06301867) held the same position from 6 April 2016 to 23 October 2018. The register for Greensands Finance lists Greensands Finance Holdings Limited (11493352) as its active controller, notified on 23 October 2018, with 75% or more of the shares and voting rights; Greensands Investments was registered there from 31 July 2018 to 23 October 2018. The register for Greensands Finance Holdings lists Greensands Investments as its only registrable controller, notified on 31 July 2018. Since 23 October 2018 the registers therefore place Greensands Finance Holdings and Greensands Finance between Greensands Investments and Southern Water Capital. According to Greensands Holdings' 2020–21 report, Greensands Finance Holdings, Greensands Finance and Greensands Financing plc (the 'MidCo' entities) were incorporated in 2018 in a financial restructuring meant to improve Southern Water's financial resilience and reduce leverage within the Southern Water Financing Group. ^{1 2 3 4}

analysisFurther up, the register for Greensands Investments lists Greensands Senior Finance Limited (06335773) as its only registrable controller, and the register for Greensands Senior Finance lists Greensands Junior Finance Limited (registration number given there as 6335757); both entries were notified on 6 April 2016 with 75% or more of the shares and voting rights and the right to appoint or remove directors. ^{5 6}

analysisThe top of the chain changed on 4 July 2025. The register for Greensands Junior Finance Limited (06335757) shows Greensands (UK) Limited (registration number given there as 6366235) as registered from 6 April 2016 to 4 July 2025, with 75% or more of the shares and voting rights and the right to appoint or remove directors, and lists Sandstone Bidco Limited (16482992) as its active controller, notified on 4 July 2025, with 75% or more of the shares; no voting or appointment rights are listed for Sandstone Bidco. Southern Water's annual report for the year to 31 March 2026 states that on 4 July 2025 Sandstone Bidco acquired the issued share capital of Greensands Junior Finance and of Southern Water (Greensands) Financing plc from Greensands (UK) Limited, which was then in administration, and became the new ultimate indirect UK holding company of Southern Water Services Limited, replacing Greensands Holdings Limited. Greensands Junior Finance became the top company of the group and the parent undertaking of the largest and smallest group consolidating Southern Water's accounts. The report describes Sandstone Bidco as representing a consortium of long-term investors with the majority investment from funds managed by Macquarie Asset Management, whose funds indirectly own a majority shareholding of Sandstone Bidco and which is treated as a related party. ^{1 2}

analysisThe registers of the three Sandstone companies each carry entries notified on 29 May 2025. The register for Sandstone Bidco lists Sandstone Midco Limited (16482495) with 75% or more of the shares and voting rights and the right to appoint or remove directors, and the register for Sandstone Midco lists Sandstone Water Holdings Limited (16482350) with the same holdings and rights. Both registers also list Macquarie Infrastructure and Real Assets (Europe) Limited (03976881) as having significant influence or control; at Sandstone Bidco it is registered only in that capacity, without a shareholding. The register for Sandstone Water Holdings, the highest UK company in the chain, lists that Macquarie company alone, notified on 29 May 2025 as having significant influence or control without a shareholding, and names no shareholder. The shareholder appears instead in the company's confirmation statement dated 28 May 2026, which reported 81,376 ordinary shares in issue, all held at that date by MSCIF Sandstone Ventures S.à r.l., a Luxembourg company. ^{3 4 5 6}

analysisAlter Domus (UK) Limited (07562881) was appointed company secretary of Sandstone Water Holdings on 13 November 2025, according to the Companies House filing history. Its London office at 30 St Mary Axe is the correspondence address recorded for Sandstone Midco, Sandstone Water Holdings and MSCIF Wight Midco Limited in their entries as registrable controllers. Alter Domus's own register of people with significant control carries an active statement, notified on 22 November 2023, that the company knows of no registrable person or registrable legal entity; three individuals were registered as its controllers from 11 April 2017 to 22 November 2023. No record shows Alter Domus holding shares in the Southern Water group. ^{3 4 7 8 9}

analysisSouthern Water Services is itself the only registrable controller of two companies. SW (Finance) I PLC (13677506) is a financing subsidiary of Southern Water Services Limited: its register lists Southern Water Services as its only registrable controller, notified on 13 October 2021, with 75% or more of the shares and voting rights and the right to appoint or remove directors, and its own accounts for the year to 31 March 2026 name Southern Water Services as its immediate parent. It issues bonds under a £6,000,000,000 multicurrency programme that, according to the supplementary prospectus of 30 July 2025, is unconditionally and irrevocably guaranteed by, among others, Southern Water Services Limited. Its accounts also state that on 4 July 2025 Sandstone Bidco Limited became its new ultimate indirect UK holding company, replacing Greensands Holdings Limited, and that Greensands Junior Finance Limited is the parent of the only group consolidating it. The register for SW (Finance) II Limited (13677558) likewise lists Southern Water Services Limited as its only registrable controller, notified on 13 October 2021, with 75% or more of the shares and voting rights and the right to appoint or remove directors. ^{1 2 3 4}