By Atsuko Fukase

TOKYO-- Mizuho Financial Group Inc. said Thursday that it has agreed to purchase the U.S. loan assets of Royal Bank of Scotland Group for around $3 billion, as Japanese companies snap up overseas assets at a record pace.

Mizuho, Japan's second-largest lender by assets, said it will acquire $36.5 billion in corporate loans and commitments from RBS in a deal that will help it boost its global presence in corporate lending and debt issuance.

While Japanese banks face soft demand for loans at home, and interest rates near historically low levels, they have large cash piles to spend in search of overseas growth. They have expanded their presence in other Asian markets in recent year, particularly in Southeast Asia. Mizuho, for example, is also in talks with Philippine conglomerate San Miguel Corp. about buying its 60% stake in Bank of Commerce, which is valued at more than $500 million, according to people familiar with the matter.

Mizuho's deal with RBS is just the latest by a Japanese company looking for opportunity abroad to offset slow growth at home. Japanese firms in a range of sectors have announced $24.9 billion of overseas mergers and acquisitions so far this year, not counting the Mizuho-RBS deal, according to data provider Dealogic. That's the most ever for the time period, exceeding last year's year-to-date total of $18.28 billion, which included Suntory Holdings Inc.'s $13.95 billion acquisition of Beam Inc.

Among recent deals, Asahi Kasei Corp. this week agreed to buy the energy-storage business of Charlotte, N.C.-based Polypore International Inc. for $2.2 billion. Last week, Japan Post Holdings Co. said it would buy Australian logistics company Toll Holdings Ltd. for $5.1 billion, while Kintetsu World Express Inc., a Japanese air freight operator, agreed to buy APL Logistics Inc. from Singapore-based Neptune Orient Lines Ltd. for $1.2 billion.

Canon Inc. said earlier this month it would acquire Axis Communications AB of Sweden for $2.8 billion, and last month trading house Itochu Corp. jointly took a joint 20% stake in China's Citic Ltd. with Thailand's Charoen Pokphand Group, with its share coming to around $5.2 billion.

The buying spree comes despite a two-year decline in the yen that has made overseas assets more expensive in the local currency. Still, bankers say withering growth prospects at home mean the yen's weakness is unlikely to slow the pace.

Japanese banks are also eyeing assets put up for sale in Asia and elsewhere by European rivals such as RBS who are pulling back from overseas markets, partly due to the need to comply with tighter global capital rules.

Including Mizuho, Japan's top three lenders have all acquired operations or assets from RBS, which is 80% owned by the U.K. government. In 2010, Mitsubishi UFJ Financial Group Inc., or MUFG, bought RBS's project-finance team and its $6 billion loan portfolio in Europe, the Middle East and Africa. In 2012, Sumitomo Mitsui Financial Group Inc. bought the RBS Aviation Capital aircraft-leasing business for $7.2 billion.

Write to Atsuko Fukase at atsuko.fukase@wsj.com

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