HSBC, Europe's largest bank, made a comeback by beating estimates in its financial results for the first half of 2018 — following a surprise fall in profits in the first quarter.

The bank said on Monday that reported profit before tax went up by 4.58 percent year-over-year to $10.71 billion in the first six months of 2018 — beating analyst estimates of $10.38 billion, according to data compiled by Reuters.

The London-headquartered bank said revenue also improved in the first half of the year: Reported revenue rose 4 percent year-over-year to $27.29 billion, also above Reuters' estimates of $27.63 billion.

Operating expenses grew to $17.5 billion in the first half of the year from $16.4 billion in the same period last year. The bank's costs have become a closely watched metric by investors after an increase expenses in the first quarter resulted in a decline in profits.

Shares of HSBC, a heavyweight on the Hang Seng Index, rose 0.83 percent after the Hong Kong market returned from a lunch break.

HSBC's chief executive, John Flint, said the results are in line with expectations.

"This is creating room to invest while maintaining our commitment to full-year positive adjusted jaws," he said in a statement accompanying the results announcement.