Eon, the German utility, trumped Gas Natural's takeover bid for Endesa yesterday, offering €29.1 billion for Spain's biggest electricity group.

The merger would be the largest global utilities deal on record and would create an energy company with more than 50 million customers across 30 countries in Europe and the Americas.

Eon, the world's largest integrated gas and electricity group by customers, said it would pay €27.50 per Endesa share - about 30 per cent more than the value of Gas Natural's share-heavy offer, announced in September.

Eon's offer represents an 8 per cent premium over Endesa's closing price on Monday, and nearly 50 per cent above its trading value before Gas Natural's surprise bid.

The bid is Europe's largest cash offer, beaten in global rankings only by Cingular's 2004 $41 billion (€34.4 billion) offer for AT&T Wireless.

The total value of the transaction could be up to €55.2 billion, with debt and minority interests.

The offer is conditional on acceptances from shareholders representing 50.01 per cent of the equity and a change in Endesa's rules limiting the voting power of a single shareholder to 10 per cent of the total.

Endesa indicated it would put the rule change to shareholders at an extraordinary meeting.