Since announcing its £3.5 billion bid for Enterprise last Tuesday, Shell has managed to buy only 11.7 percent of the share capital by Friday, which according to many in the market is evidence enough that many investors are reluctant to let go of their shares just now.

Many investors were hoping for a counteroffer from Italian energy giant Eni SpA that did not materialise. However other potential suitors include TotalFinaElf, Statoil, Chevron Corp as well as Conoco.

Shell, which is expected to have to wait around four weeks for regulatory approval of its purchase, will post its offer document early next week and approval for the Shell offer is expected to be forthcoming if no rival emerges.

Last Friday Enterprise shares were trading at 723.5 pence.