Mitsubishi UFJ Financial Group Inc. probably led a slight increase in first-quarter profit at Japan's biggest banks as gains in fee income and overseas lending made up for shrinking loan profitability at home.

Combined net income at Mitsubishi UFJ, Sumitomo Mitsui Financial Group Inc. and Mizuho Financial Group Inc. rose 1 percent to ¥632.1 billion ($5.1 billion) in the three months to June, according to the average estimate of six analysts surveyed by Bloomberg before earnings reports due Friday.

The Tokyo-based banks have announced acquisitions abroad worth about $6 billion this year as low interest rates in Japan continue to squeeze margins. They are also stepping up domestic sales of investment products as people begin shifting some of their savings to riskier assets amid a stock market rally.