A Guardian investigation unpicks complex web of investment firms, wealth funds and tax haven-based businesses that own most of sector

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Foreign investment firms, private equity, pension funds and businesses lodged in tax havens own more than 70% of the water industry in England, according to research by the Guardian.

The complex web of ownership is revealed as the public and some politicians increasingly call for the industry to be held to account for sewage dumping, leaks and water shortages. Six water companies are under investigation for potentially illegal activities as pressure grows on the industry to put more money into replacing and restoring crumbling infrastructure to protect both the environment and public health.

More than three decades after the sector was sold off with a promise to the public they would become individual small shareholders or “H₂Owners”, control of the water industry has become dominated by overseas investment vehicles, the super-rich, companies in tax havens and pension fund investors. The ownership structure is such that transparency and accountability are limited, according to Dr Kate Bayliss, a research associate with the department of economics at Soas University of London.