Anglian Water (AWG) saw its share price shoot upwards by 11 per cent on morning trading following rumours that the water provider could receive a takeover bid.
It is currently unclear whether or not another water company has made the offer, although experts believe this to be unlikely as it would constitute a breach of competition rules governing the utilities sector.
Instead an investment firm is the most likely source of the current speculation, with AWG careful to emphasise that there is no certainty about a firm offer eventually being made.
"The board of AWG notes the rise in AWG's share price and confirms that it has received a preliminary approach which may or may not lead to an offer being made for the company," AWG said in a statement.
"There can be no certainty that any offer will be made."
AWG, worth £2.2 billion, provides water for 5.5 million in the east of England. It employs 9,000 people and turned over £1.5 billion in 2005-6.
Issuing its annual results on May 31st, AWG registered dramatically improved operating profits of £377.9 million, up from the previous year's equivalent of £288.8 million.