National Commercial Bank and Riyad Bank are seeking advisers for a potential merger that would create the Gulf region’s third-biggest lender with $182 billion in assets, according to people with knowledge of the matter.

The banks have sent out so-called request for proposals to firms including Citigroup Inc., Credit Suisse Group AG, Goldman Sachs Group Inc., HSBC Holdings Plc, JPMorgan Chase & Co. and UBS Group AG, the people said, asking not to be identified because the matter is private.

Formal advisers for the deal, which could be biggest bank merger for almost three years, could be appointed this month, the people said. The proposed combination has the backing of the Public Investment Fund, the sovereign wealth fund that owns about 44 percent of National Commercial Bank and 22 percent of Riyad Bank, the people said. No final decisions have been made and the banks may choose other advisers, they said.

Saudi Arabia is exploring mergers to boost its financial services industry after the combination of Saudi British Bank and Alawwal Bank. National Commercial Bank, which has a market value of about $38 billion, last month said it started talks with Riyad Bank, which is worth about $15.7 billion, after Bloomberg News reported the kingdom was weighing more bank combinations.

The merger would rank as the biggest banking deal globally since Abu Dhabi’s two biggest banks agreed in March 2016 to combine, according to data compiled by Bloomberg. It would also follow the merger of HSBC Holdings local unit with a rival part-owned by Royal Bank of Scotland Group Plc in a $5 billion deal.

Banks in neighboring Gulf countries are also in talks to merge to cut costs and improve efficiencies. Three of Abu Dhabi’s state-linked banks are in talks to combine into an institution with $110 billion of assets. The negotiations follow a tie-up between Abu Dhabi’s sovereign wealth funds last March.

Credit Suisse, Citigroup, Goldman Sachs, UBS and the Public Investment Fund declined to comment. JPMorgan, HSBC, National Commercial Bank and Riyad Bank didn’t immediately respond to requests for comment.