Mitsubishi UFJ Financial Group Inc. agreed to buy DZ Bank's aviation finance division in one of its biggest acquisitions since it was created in 2005.

The assets MUFG bought from Germany's second-largest bank, held by its subsidiary DVB Bank, include a loan portfolio of €5.6 billion (¥710 billion) as well as the unit's employees and "parts of the operating infrastructure," according to news releases from both banks on Friday.

The deal is the latest for Japan's biggest bank in a spate of acquisitions abroad as it seeks to make up for diminishing returns in a country that's beset by rock-bottom interest rates and slow economic growth.