Complaints of corruption in Hong Kong’s finance and insurance sectors rose by almost 20 per cent to 177 in the first 11 months of this year, the city’s graft buster revealed on Wednesday, even as it said that this did not point to a worsening problem.

However just weeks ago, Independent Commission Against Corruption (ICAC) mounted a large scale investigation of listed company Convoy Global Holdings, in the city’s largest corruption crackdown in a decade.

It arrested three senior executives who were suspended by Convoy’s board. The company is a financial adviser to Hong Kong’s Mandatory Provident Fund pension scheme and a provider of retirement planning and insurance services.

ICAC said the rise in complaints this year was in comparison to 148 cases in the same period last year. Companies were accused of using forged documents to deceive others, receiving bribes for granting loans and referring business, and questionable awarding of contracts, among other things.

But Chow Chung-kong, the chairman of ICAC’s advisory committee on corruption, said the figure did not suggest that graft was worsening in the city.

“No matter how tight the regulations are, we cannot prevent the occurrence of illegal activities,” Chow who is also chairman of the Hong Kong Exchanges and Clearing (HKEX), said.

Different agencies had been working closely to crack down on and prevent bribery, Chow added, at a press conference where he and three other chairpersons of ICAC advisory committees gave an annual review of the graft situation in the city.

“The ICAC and Securities and Futures Commission mount joint operations if unlawful activities emerge. I think it is an effective way to crack down on the problems. I do not find a deteriorating trend,” Chow said, adding that the graft buster, the HKEX and the Securities and Futures Commission (SFC) met regularly to discuss the development of listed companies.

The ICAC had also issued anti-corruption guidelines for listed companies last year.

The graft buster said the city is a leading international financial hub in the region and it would spare no effort to defend Hong Kong’s internationally acclaimed reputation as one of the cleanest places to do business.

Asked for updates on the investigation into former chief executive Leung Chun-ying’s HK$50 million payout from Australian firm UGL, the chairwoman of ICAC’s operations review committee, Maria Tam Wai-chu, said she would not comment on individual cases.

ICAC launched its investigation into Leung in 2014 after it was made known that he did not declare his receipt of the money between 2012 and 2013, during his tenure as the city’s leader. Leung said the amount was agreed on as part of a business deal before he took office.

Tam added that the operations department regularly updated her group on cases and said she believed the agency would handle the case fairly, regardless of the social status of those under scrutiny.

As a rule, no investigation can be terminated without the committee’s endorsement.

Overall, the ICAC received a total of 2,648 corruption complaints that were not election-related in the first 11 months of this year, representing a slight drop of 2 per cent when compared to the same period last year.

Two-thirds of the complaints concerned the private sector, while 27 per cent related to government departments and 6 per cent involved public bodies.

This year, 80 per cent of people prosecuted for graft were convicted, compared to 73 per cent last year. The case-based conviction rate was 82 per cent, compared to 79 per cent last year.