"The risk of a market placement penalizes the stock," comments one trader after Eni turned negative following news launched by Bloomberg that the Treasury is considering selling 4 percent of its capital once the oil company completes a buyback plan, aiming to collect 2 billion euros.

The government owns 32.4 percent of Eni, 4.7 percent directly and 27.7 percent through Cdp.

As early as November, Reuters wrote that some investment banks had proposed that the Treasury divest part of the public stake in the energy group in light of the fact that completion of the buyback -- by April 2024 -- and cancellation of the shares purchased would allow Rome to reduce the stake without losing control of the company.

In late November, Economy Minister Giancarlo Giorgetti had said that reducing the state's share in Eni by exploiting the effects on the shareholder base of the company's buyback plan was "a good idea."

(Rome Editor, editing Stefano Bernabei)