TOKYO (Reuters) - Mitsubishi UFJ Financial Group Inc (MUFG), Japan's largest lender by assets, on Tuesday reported a 70.3% plunge in first-quarter net profit due to a one-off loss related to the sale of MUFG Union Bank.

Mitsubishi UFJ, which owns 21.5% of Wall Street bank Morgan Stanley, reported net profit of 113.7 billion yen ($869.1 million) for the April-June period, against 383.1 billion yen a year earlier.

The Japanese bank maintained its full-year profit forecast of one trillion yen, a 12% drop from the previous year when it posted a record profit. The outlook compared with an average forecast of 1.05 trillion yen from 13 analyst estimates compiled by Refinitiv.

($1 = 130.8300 yen)

(Reporting by Makiko Yamazaki; Editing by Kirsten Donovan)