By Christopher Bjork 

MADRID--Italy's Enel SpA has raised EUR3.13 billion ($3.91 billion) from the sale of a large stake in its Spanish power utility Endesa SA to institutional and retail investors.

Enel priced Endesa's shares in the sale at EUR13.5 each, Endesa said in a regulatory filing on Friday, representing a slight discount to Thursday's closing price of EUR13.71.

The Italian utility has unloaded a 21.92% tranche of Endesa stock, including an overallotment option granted to its advisers before the start of the sale process. Before the sale, Enel had a 92% stake in the Madrid-listed company.

The sale comes weeks after Enel took over Endesa's Latin American unit and Endesa distributed an unusually large EUR14.6 billion ($18.2 billion) dividend that was largely to the benefit of the Italian utility.

Enel took over Endesa in 2007 after a multiyear bidding battle with Germany's E. ON AG and just before Spain plunged into a deep economic slump.

Spain's then-Socialist government came under fire for allowing Enel, which is controlled by the Italian state, to acquire Endesa, which had been privatized just a few years before.

Demand for Endesa shares among institutional investors was 2.2 times the shares assigned, Endesa said. Among retail investors, demand was 1.7 times the shares initially on offer. Enel earlier this week increased the number of shares sold to retail investors.

Banco Santander SA, Banco Bilbao Vizcaya Argentaria SA, Credit Suisse Group AG and J.P. Morgan Chase & Co. were joint global coordinators on the deal, while Goldman Sachs Group Inc., Morgan Stanley and UBS AG were joint bookrunners. Mediobanca SpA advised Enel.

Write to Christopher Bjork at christopher.bjork@wsj.com

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