MONTREAL -- National Bank (TSX:NA) saw a 37 per cent drop in its first-quarter profit due in large part to a decision to write off its investment in Maple Financial Group.

The Montreal-based bank -- the smallest of Canada's six major banks -- says its net income for the quarter totalled $261 million, down from $415 million a year earlier.

Diluted earnings per share were 67 cents for the three months ended Jan. 31, down from $1.16 a year earlier.

National Bank announced on Feb. 7 that it would write off the value of its 24.9 per cent interest in Maple Financial after a German financial regulator shut down its Maple Bank subsidiary.

The decision cost the bank $145 million after taxes.

Excluding several specified items, including the Maple Bank loss, National Bank says it would have earned $427 million or $1.17 per share in the quarter -- up four per cent from $410 million or $1.14 per share a year ago.

The bank's personal and commercial operations contributed $184 million of net income, up eight per cent from last year.

Net income from wealth management was up four per cent to $77 million from $74 million while its financial markets arm contributed $41 million of net income, down from $177 million a year earlier -- mainly because of Maple Financial.

Maple Financial Group is unrelated to Maple Acquisition Group, which bought the TMX in 2012.