TORONTO -- Royal Bank of Canada's profit in the fourth-quarter edged lower compared with a year ago, due in part to lower results at some business units and increased provisions for credit losses, RBC announced Wednesday.

The Toronto-based bank reported net income nearly $3.21 billion or $2.18 per diluted share in the quarter ended Oct. 31, down from $3.25 billion or $2.20 per diluted share in the same quarter last year.

Its adjusted diluted cash earnings per share amounted to $2.22 for the quarter, which was below the average analyst estimate of $2.28 per share, according to financial markets data firm Refinitiv.

Royal Bank's total provisions for credit losses rose to $499 million from $353 million a year earlier, mainly at its banking, wealth management and capital markets units.

RBC said its personal and commercial banking unit, which increased net income by five per cent or $80 million to $1.62 billion, benefited from solid housing activity, a growing sales force and favourable interest rate environments.

However, the core banking unit also increased its provisions for credit losses and recorded higher provisions for impaired loans by $70 million or 22 per cent compared with last year's fourth quarter to $387 million.

Net income at wealth management rose 32 per cent or $176 million to $729 million, including a gain on the sale of a private debt business. Wealth management also benefited from higher average fee-based client assets and net sales.

Offsetting these positives, RBC's insurance unit's net income, which fell 11 per cent or $36 million compared with last year to $282 million and net income at capital markets fell 12 per cent or $82 million to $584 million.

Net income at RBC's treasury services fell 71 per cent or $110 million from a year ago to $45 million, primarily due to severance and related costs associated with repositioning of the business.