(Updates with details, quote from Eneco letter)
By Toby Sterling
AMSTERDAM, July 7 (Reuters) - The Hague joined Rotterdam on Friday in saying it wanted to sell its stake in Eneco, bringing an outright sale of the Dutch energy company or an initial public offering (IPO) of its shares one step closer.
Together the two Dutch municipalities hold 48.3 percent of Eneco and if more than 50 percent of shareholders decide to sell out by Oct. 31, Eneco will consider whether to seek a buyer or initiate an IPO, probably next year.
Eneco's faces an uncertain future after it lost a decade-long battle against a government decision to separate grid operators from electricity generators. The company was split on Jan. 31 into grid operator Stedin NV and Eneco Groep NV.
That triggered an external review of Eneco's future by a commission set up to protect the interests of the 53 Dutch municipalities that own the company.
The review, published on Friday along with a statement from The Hague, which owns 16.6 percent of Eneco, said it had an annual operating profit of about 400 million euros ($456 million) and was worth roughly 2.7 billion euros.
In a letter to shareholders, Eneco said they should hold onto their stakes given that the company was a "successful, sustainable company with structural dividend income", while a sale would only give the cities a one-off windfall.
However, the commission said in a letter dated July 5 that Eneco had painted a "too one-sided" picture of its finances and not informed shareholders of risks to its business model, notably from falling energy prices and the loss of clients.
Eneco is being advised by ABN Amro while the cities are being advised by Aperghis & Co.
$1 = 0.8781 euros Additional reporting by Bart Meijer; editing by David Clarke