(Adds A2A comment)
MILAN/PODGORICA, May 18 (Reuters) - Italy's biggest regional utility A2A is working with investment bank Rothschild to sell its stake in Montenegrin power monopoly EPCG by the year end, three sources with knowledge of the matter said.
A2A, which first invested in EPCG in 2009, has an option between June and September to sell its 41.7 percent stake to the Montenegrin government for 250 million euros ($278 million).
The option was negotiated by the new management team that took the helm at A2A in 2014.
"By the end of September we'll decide whether to leave or not," A2A Chief Executive Valerio Camerano told Reuters on Thursday when asked about the group's intentions.
Montenegro's government, which owns the rest of EPCG, has in the past complained about a low level of investment by A2A. The government has called on A2A to back its plans for a new coal-fired unit at its Pljevlja power plant.
Although it has a minority stake, A2A jointly manages EPCG and has previously said it wants investment return guarantees, management autonomy and a clear regulatory framework.
A2A, controlled by the cities of Milan and Brescia, spent around 436 million euros to buy a 43.7 percent holding in EPCG, which it has since cut to 41.7 percent.
It now wants to exit Montenegro to be able to focus on growing its business in Italy, one of the sources said.
Italian governments have been trying for years to get Italy's more than 1,500 utilities controlled by cities and regions to consolidate and become more efficient
Rome is keen for the four big listed regional utilities in Italy to spearhead the process.
Rothschild declined to comment while A2A declined to comment on the role of the bank. ($1 = 0.8985 euros) (Reporting by Stephen Jewkes and Giancarlo Navach in Milan, Petar Komnenic in Podgorica; editing by Alexander Smith and David Evans)