Debt fears
Since 2016, profits have not covered the cost of paying interest on its debt, investment costs, and dividend payments, according to Russ Mould, investment director at AJ Bell.
Professor David Hall of University of Greenwich said investors are reluctant to take on the risk of further investment due to fears it will not be repaid.
He said the £500m of investment was the only time investors had put their own cash into the company since it was privatised in 1989, having instead raised cash for investment from customer bills.
For the last five years, its owners have backed the decision not to pay any dividends to external shareholders. It has however paid dividends internally to its parent company.
If the government is forced to step in, Professor Hall said shareholders rather than the public were likely to lose money.
Water bills have been on the rise, with the annual bill for an average household in England and Wales hitting £448 in April.
Bills are set to rise again in 2025 by about £42 per household on average over a "long time frame", former Environment Secretary George Eustice said on Wednesday.
It came after the Times reported bills could rise by as much as 40%, a figure Mr Eustice dismissed, saying it would be "far lower".
Shadow energy secretary Ed Miliband said the situation at Thames Water was "an absolute scandal".Asked whether the company should be nationalised, he replied: "I don't think the answer to the water company's crisis is to pay out billions of pounds to shareholders, when that money could be going into sorting out what is happening in the water industry".
Separately, Chancellor Jeremy Hunt met with regulators, including Ofwat, early on Wednesday. He told them that they needed to "work at pace" to ensure businesses reflected any falling costs in the prices they charged customers.
Also at the meeting were regulators from the energy, financial and communications sectors, to face questions about whether there is a profiteering problem and what they are doing to tackle it.
https://www.bbc.co.uk/news/business-66039170