Investors in Italy's Enel, one of Europe's biggest utilities, vote on May 10 to name a new board. The Treasury owns 23.6% of Enel.

In a management shake-up that has unnerved some investors, Rome has indicated Flavio Cattaneo, a former chief at power grid operator Terna currently at high-speed train operator Italo, to replace veteran CEO Francesco Starace.

The Treasury also indicated as chairman Paolo Scaroni, a former boss at Enel and state-owned energy firm Eni.

Covalis Capital, which holds around 1% of Enel, has proposed former top banker Marco Mazzucchelli for the chairmanship as it filed a slate of independent candidates.

"Should nominee Mazzucchelli be elected to the board, he would be better placed to safeguard board-level independent oversight and serve as a better counterbalance to the presence of the CEO on the board," Glass Lewis wrote in its report.

The London-based hedge fund has complained of an "opaque process" regarding Enel, adding it was unclear "what the government's proposed slate stands for or what their plan is."

A group of institutional investors backed by asset manager association Assogestioni has filed a third slate of nominees, without CEO and chair candidates.

In its report, Glass Lewis recommended Enel investors vote for Assogestioni's board nominees as "they are better suited to represent a wider group of minority shareholders".

(Reporting by Francesca Landini, writing by Gianluca Semeraro, editing by Federico Maccioni and Valentina Za)