Dubai's main share index gained 1.5%, with Emirates NBD Bank rising 4.1%. Shariah-compliant lender Dubai Islamic Bank was up 2.4%.
The Abu Dhabi index declined 1.8%, weighed down by a 3.8% slide in First Abu Dhabi Bank (FAB). FAB, the United Arab Emirates' largest bank, said on Wednesday it has $73.2 million of exposure to agri-trader Phoenix Commodities and related entities.
This was the biggest exposure so far disclosed by a UAE bank to the group, which has entered liquidation after amassing more than $400 million in potential trading losses, according a document prepared by the liquidators and seen by Reuters.
Saudi Arabia's benchmark index added 0.6%, extending gains from the previous session. Al Rajhi Bank gained 1.1% and petrochemical maker Saudi Basic Industries (SABIC) was up 2.2%.
Al Rajhi Bank reported a net profit of 2.38 billion riyals ($633.65 million) in the first quarter, down from 2.57 billion riyals a year earlier. However, the net profit was higher than the previous quarter.
Saudi Aramco's shares were up 0.2%. On Tuesday, the world's top oil exporter reported a 25% fall in first-quarter net profit, which it blamed on slumping oil prices.
In Qatar, the index dropped 1%. Most of the stocks on the index were in red, including Qatar National Bank, which was down 1.7%.
Outside the Gulf, Egypt's index retreated 1.8%, with most of blue-chip stocks falling. El Sewedy Electric plunged 8.8% following a more than 50% decline in first-quarter net profit.