The Hong Kong stock exchange has returned an IPO application sponsored by China’s leading investment bank, sending a strong signal of increased scrutiny. The listing application for Inner Mongolia Xingye Silver & Tin Mining, which is already listed on the A-share market in Shenzhen, was returned by Hong Kong Exchanges & Clearing (HKEX) on June 22, according to information released by the exchange operator on Thursday. It was the first initial public offering application to be returned in Hong Kong in seven months, according to public records, and came amid increasing regulatory pressure as the city’s exchange experiences an IPO boom. According to Xingye’s preliminary prospectus, which was released at the end of May, the listing was sponsored by China International Capital Corporation (CICC), which was the top sponsor of Hong Kong IPOs in the first half of this year. Since 2014, if HKEX has deemed a listing application incomplete, it has returned the filing and publicly disclosed the sponsor’s name on its website. Twenty-six applications have been returned: 16 for the exchange’s main board and 10 for its GEM board. HKEX launched a market consultation in March on expanding the regime to include law firms and auditors involved in substandard listing applications. Hong Kong’s securities watchdog, the Securities and Futures Commission, has also stepped up supervision this year, issuing severe warnings to 13 major sponsor firms and limiting each principal to supervising a maximum of five active IPOs at one time. Xingye said in an announcement issued on Thursday that the return was “due to the need to update the effective date of its mining report and the expected prospectus issuance date”. It said it planned to resubmit its IPO application before the end of September. Beijing-headquartered CICC said in a statement issued on Thursday that it had completed 54 IPOs and share placements in Hong Kong this year, helping to raise over US$33 billion. It said it was the top sponsor in the market, accounting for 30 per cent of applications. In an earlier exchange filing it estimated its first-half net profit would be between 7.71 billion yuan (US$1.14 billion) and 8.23 billion yuan, up 78 per cent to 90 per cent year on year.