Following news of Endesa's largest ever dividend payout on June 30, the two rival suitors for the Spanish energy group have seen their takeover bids decrease in value.

Under the terms laid out in the prospectuses of the respective bids, both E.ON and Gas Natural have seen their bids lowered after Endesa went ahead with a huge E2.2 billion dividend payout to shareholders in the wake of a telecoms divestment in 2005.

Gas Natural’s bid now stands at around E20.8 billion, or E5.98 per share, while E.ON’s bid is down from an initial E29.1 billion to around E26.9 billion.

Both bids are currently log jammed by regulatory investigations following the Spanish government’s controversial attempts to block a foreign takeover of Endesa.