SFC market statistics for 2025 put total HKEX market capitalisation at roughly HK$38 trillion, and the commission's chief executive Julia Leung took a portion of that number to Shanghai on Thursday: the northbound Stock Connect holdings that HKEX data places at roughly HK$3.1 trillion, all deployed into A-share companies whose sustainability disclosures satisfy China's Ministry of Finance standards rather than the ISSB framework HKEX now requires on its own side. HKEX phased in mandatory ISSB-aligned climate disclosure for large-cap issuers from January 2025 and for mid-cap issuers from January 2026. China's Ministry of Finance published its Sustainability Disclosure Standards in February 2024, with mandatory A-share application from fiscal 2026. Both regimes are live. They diverge on which supply-chain and customer-use emissions count as significant enough to report -- the Scope 3 materiality threshold -- and on how fast an outside auditor must verify the figures. Leung met CSRC Shanghai Bureau officials in what the SFC called a cross-border regulatory exchange, the first at commission-head level since both frameworks were simultaneously in force.

The SFC and CSRC have run parallel regulatory exchanges since Stock Connect opened in 2014. The disclosure divergence is new. Hong Kong and mainland investors now trade across a border where sustainability reporting draws those significance thresholds differently, and the practical cost falls on roughly 230 H-share companies, mainland enterprises dual-listed in both markets, each filing annual sustainability reports under two standards that do not match. A compatibility determination before Q4 2026 would give those companies adequate lead time before the January 2027 reporting cycle opens.