Advisers to Gaz de France and Suez will share €290m ($450m) in fees for steering the merger of the state-controlled gas group and the private utility to completion next month, after two and a half years of negotiations.

The GdF-Suez merger will create one of Europe’s biggest energy groups with sales of €74bn, according to the fairness opinion published in the merger prospectus on Monday.

The document also shows that the cost of the transaction has escalated from €230m as the fiendishly complicated process has encountered political, legal and union obstacles. At least 10 banks were used by the two companies, and a host of lawyers, strategy consultants and labour relations experts.

Insiders estimated that the banks involved received roughly half of the €290m in fees, representing a remarkably low fee for the extended process. “Banks have not made a fortune out of this,” insisted one adviser on Monday. Analysts also suggested that the fees – representing 0.3 per cent of Monday’s combined market value – were not exorbitant, with bankers perhaps hoping to win more privatisation business from the French state.

Merrill Lynch, Goldman Sachs, Rothschild, Lazard and Société Générale advised Gaz de France while JPMorgan, BNP Paribas, Blackstone, Banca Leonardo France and HSBC acted for Suez.

The prospectus was filed with the French AMF stock market regulator as one of the final steps before the companies call their shareholder meetings on July 16 to vote on the merger. The fairness opinion, compiled by Oddo Securities of France, confirmed the fairness of the terms at 21 Gaz de France shares for 22 Suez shares. There was even a small premium for Suez shareholders in a deal billed as a merger of equals.

However, it questioned some of the methodology used by advisers to the deal in valuing the combined business to be created, in particular the use of discounted cash flow measures. The differences in the profiles of the two groups meant Oddo did not consider such methodology appropriate for its own calculations.

The prospectus also confirmed that Suez shareholders will receive one Suez Environnement share for every four Suez shares owned, in the spin-off that is planned at the same time as the merger. Suez was forced to spin off 65 per cent of the water and waste business to secure government backing.

Suez Environnement on Monday said it expected average annual organic sales growth of more than 5 per cent in 2008-2010 and dividend growth of at least 10 per cent a year.

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