By Jason Ng and P.R. Venkat 

Malaysia's CIMB Group Holdings Bhd. has launched a review of some of its operations, which could lead to job cuts and spur an exit from some unprofitable businesses and markets, people with knowledge of the matter said Friday.

The Malaysian bank accelerated its review after the collapse of an $18 billion three-way merger plan with smaller local rivals last month. It is currently focused on CIMB's investment banking business, people familiar with the matter told The Wall Street Journal, but the review is also looking at other areas of the bank's operations. The investment-banking business includes the Asian equity operations CIMB bought from British bank Royal Bank of Scotland Group PLC three years ago and has offices in Hong Kong, Singapore and Australia.

It wasn't immediately clear when the review began, but an announcement could come in the next few days, these people said.

"The review may involve restructuring and reorganization to lower costs, " one of the people said.

CIMB has been trying to lower its cost base, which is one of the highest among Malaysian banks. At the end of September, Malaysia's second largest bank by assets had a cost-to-income ratio of 58%. By the same measure, the cost-to-income ratio for Malayan Banking Bhd., Malaysia's largest bank, was about 50%, according to AllianceDBS Research.

CIMB, RHB Capital Bhd. and Malaysia Building Society Bhd. ended talks last month on a deal that would have created one of Southeast Asia's largest banking groups. The deal was called off "in light of current economic conditions," with the three banks saying they couldn't arrive at a value-creating transaction for all stakeholders.

That deal would have propelled CIMB to the top of the country's crowded banking market, while creating a megabank with over $180 billion in assets. Malaysia is home to 27 local and foreign lenders with thousands of branches competing for business in a nation of 30 million people.

The restructuring and potential cutbacks call into question the pan-Asian strategies of the region's banks in recent years.

Last month, emerging markets-focused Standard Chartered PLC said it was shutting its stock-trading and underwriting business and shedding thousands of mostly Asia-based retail banking jobs. Japan's Nomura, which bought Lehman Brothers' Asian and European operations in 2008, began scaling back on global ambitions a few years ago.

CIMB's deal to buy parts of RBS's business almost three years ago gave the Malaysian bank some of the British lender's cash equities, equity capital markets and corporate-finance businesses in Asia with around 400 people. RBS began selling off global assets after getting bailed out by the British government during the 2008 financial crisis.

CIMB's net profit fell 16% in the third quarter to 890.3 million ringgit ($251.5 million) while its net interest margin, a measure of profitability from lending, fell 2.86% in September compared with 2.87% a year earlier. The company is due to report fourth-quarter earnings by end-February.

Write to Jason Ng at jason.ng@wsj.com and P.R. Venkat at venkat.pr@wsj.com

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