* JPMorgan has been hired to advise mBank - sources
* Goldman Sachs is advising Commerzbank - sources
* Sale to finance Commerzbank restructuring (Updates with new lede, context and background)
WARSAW/FRANKFURT (Germany), Oct 11 (Reuters) - Commerzbank is sounding out potential buyers of its stake in Polish lender mBank ahead of a formal sale process which is expected to launch in coming months, people familiar with the matter said.
MBank has hired JPMorgan as an advisor, while Goldman Sachs is advising Commerzbank, two sources said.
Germany's second-largest lender, which is seeking funds to finance its recently announced restructuring, said in September its supervisory board had approved plans to sell the 69.3% stake in mBank, worth about $2.65 billion.
MBank is the fourth-largest lender by assets in Poland, Eastern Europe's biggest economy. The top three lenders include two state-run banks, PKO BP and Pekao, and Santander Bank Polska.
The country's banking sector suffered a blow last week, when the European Union's top court ruled in favour of Polish consumers who took out mortgages in Swiss Francs, allowing them to ask Polish courts to convert the loans into the local zloty currency.
MBank has one of biggest portfolios of Swiss franc-denominated mortgages, a potential source of losses for the lender.
However, a senior banking source said mBank was a "very attractive asset", adding that potential bidders may emerge near the end of the year.
The other source said there was interest from within Poland and beyond and a formal sale process could be launched this year or early next year following informal talks that are currently underway.
mBank and Commerzbank declined to comment on Friday. JPMorgan and Goldman Sachs in Germany didn't respond to requests for comment. Poland's ruling nationalist Law and Justice (PiS) party has tightened control over the banking sector and signalled a desire to increase domestic ownership. "Generally speaking I'm in favour of increasing Polish ownership," Poland's Prime Minister, Mateusz Morawiecki, said last month when asked whether any of Poland's state-run banks would be interested in mBank. (Reporting by Alicja Ptak, Arno Schuetze, Patricia Uhlig, and Marcin Goclowski; Editing by Alexander Smith and Kirsten Donovan)