Heightened market volatility drove up National Bank of Canada trading revenue and first quarter profits, its chief executive said Friday.

"When you have heightened levels of volatility, often, it does drive more transactions, so we did see more trading activity with our clients during the first quarter," Laurent Ferreira said on an earnings call.

National, along with other Big Six banks that have reported so far, surprised analysts to the upside especially on the amount of trading revenue they brought in during the quarter that ended Jan. 31.

Ferreira said that the bank has however positioned itself defensively so that it doesn't get caught out by a swing in trading revenue in the other direction.

"Are we immune? No. No one's immune. But the way we built the business is we want to make sure that through volatile times, we can keep growing our franchise."

The bank reported trading revenues of $464 million for the quarter, up from $276 million the previous quarter and from $375 million from a year earlier.

Barclays analyst John Aiken said that the trading revenue was a big boost for the bank, but that it reported positive gains across much of its operations.

"National posted strong earnings, supported by growth in each of its segments. NA also benefited from strong trading revenues but saw continued volume growth, improved efficiency and a renewed strong performance from its international operations," he said in a note.

Overall, the Montreal-based bank reported a first-quarter profit of $932 million, or $2.65 per diluted share, compared with $761 million or $2.14 per share a year earlier.

Revenue totalled $2.47 billion, up from $2.22 billion.

On an adjusted basis, National Bank says it earned $2.65 per diluted share compared with an adjusted profit of $2.15 per diluted share a year earlier.

Analysts on average had expected an adjusted profit of $2.23 per share, according to financial markets data firm Refinitiv.

The quarter included a $2-million reversal of its provisions for credit losses compared with the $81 million it set aside for bad loans in the same quarter last year.