Most major Gulf stock markets weakened on Wednesday, largely pulled down by losses in banks, but Abu Dhabi bucked the trend on the back of top lender First Abu Dhabi Bank (FAB).

Saudi Arabia's benchmark index retreated 0.2%, offsetting earlier gains in the day. Samba Financial Group 1090.SE declined 1.6%, while Saudi British Bank was down 1.7%.

State-owned oil giant Saudi Aramco slipped 0.3% to 34.5 riyals. EFG Hermes on Wednesday initiated Aramco's coverage with a "neutral" rating, in line with most other brokerages, and set a target price of 34 riyals ($9.06) per share. 

The Abu Dhabi index gained 1% with First Abu Dhabi Bank rising 1.4% and International Holding soaring 14.9%.

United Arab Emirates' largest lender, FAB, is in talks potentially to acquire the Egyptian subsidiary of Lebanon's Bank Audi, Reuters reported, citing two sources familiar with the matter.

Bank Audi Egypt has grown from a three-branch operation acquired by Bank Audi in 2005 to 50 branches with total assets of $4.4 billion at the end of September, Bank Audi's Chief Financial Officer, Tamer Ghazaleh, said last week, when he told Reuters the bank was considering selling the unit.

In Dubai, the index fell 0.2%, driven down by an 8.6% plunge in Mashreq Bank and a 1% decrease in Emaar Properties .

Qatar's index eased 0.1% as market heavyweight Industries Qatar dropped 0.5% and Qatar Fuel  was down 0.7%.

However, it saw some support from Qatar National Bank and Masraf Al Rayan , which were up 0.3% and 0.5%, respectively.

The latter reported a higher annual profit on Tuesday.

Outside the Gulf, Egypt's blue-chip index added 0.8%, buoyed by a 0.9% increase in the country's biggest lender, Commercial International Bank, and a 1.7% rise in El Sewedy Electric.

($1 = 3.7511 riyals)

(Reporting by Ateeq Shariff in Bengaluru; editing by Nick Macfie) ((AteeqUr.Shariff@thomsonreuters.com; +918067497129;))