UPDATE 4-Caisse d'Epargne top execs resign after trading loss

* Chairman, CEO, finance head resigns after trading loss

* Bernard Comolet named new chairman, Alain Lemaire CEO (Adds CEO, finance head resignation, new board members)

By Sudip Kar Gupta and Anna Willard

PARIS, Oct 19 (Reuters) - The chairman, chief executive and finance head of Groupe Caisse d'Epargne resigned on Sunday, following a 600 million euro ($808 million) trading loss at the French mutual bank which drew the anger of France's president.

"I accept full responsibility," Chairman Charles Milhaud said in a statement.

Chief Executive Nicolas Merindol and finance head Julien Carmona also resigned from their posts.

Caisse d'Epargne said Bernard Comolet would become its new chairman, while Alain Lemaire would become chief executive.

Both Comolet and Lemaire are already at the group. Comolet is the head of the Caisse d'Epargne dealing with the Paris region, while Lemaire runs the Caisse d'Epargne branch dealing with the Provence-Alpes-Corse region.

Last week Caisse d'Epargne, which is planning to merge with Banque Populaire, revealed the trading loss which occurred due to a small team of traders making a disastrous bet on the stock markets.

The loss prompted Economy Minister Christine Lagarde to ask for a special audit of all banking institutions in France, and President Nicolas Sarkozy called the situation "unacceptable."

European Central Bank President Jean-Claude Trichet said he was shocked by the losses at the bank.

"When we know who is responsible, we must obviously draw conclusions," he said on RTL radio.

MERGER

Milhaud is the latest scalp claimed by the global credit crunch. In Britain, Royal Bank of Scotland (RBS.L) chief executive Fred Goodwin was ousted after the British government part-nationalised the bank following huge writedowns on structured products.

The former heads of Franco-Belgian bank Dexia (DEXI.PA) were also forced out following a bailout package by the governments of France, Belgium and Luxembourg.

Caisse d'Epargne said the "small team" of traders behind the trading loss had exceeded their trading risk limit and had been punished by the bank.

The incident was reminiscent of a 4.9 billion euro loss announced in January by Societe Generale (SOGN.PA), France's second-biggest listed bank, and blamed on junior dealer Jerome Kerviel.

Both Caisse d'Epargne and Banque Populaire have said the loss would not affect their tie-up, and Caisse d'Epargne again reiterated its plans to proceed with the merger on Sunday.

The merger will likely create France's second-biggest retail bank after Credit Agricole (CAGR.PA).

Banque Populaire and Caisse d'Epargne said the new group would have assets of 40 billion euros and 480 billion of savings and deposits.

Caisse d'Epargne and Banque Populaire also own 70 percent of investment bank Natixis (CNAT.PA), which has been hit hard by the credit crisis and needed a capital increase to boost its solvency ratio.

Natixis shares, which closed up 1.9 percent on Friday, have fallen around 76 percent since the start of the year, making it France's worst performing bank stock.

(Additional reporting by Matthieu Protard) (Editing by Will Waterman and Bernard Orr)