Southbound Stock Connect inflows crossed US$152 billion in cumulative 2026 flow as of this week, per South China Morning Post sourcing HKEX data, which puts mainland capital at roughly 40 percent of total HKEX daily turnover on the sessions where the number holds (and which confirms what the secondary market has been showing for six months: the marginal price-setter in most mid-cap Hong Kong names is now a Shenzhen or Shanghai account that cannot hedge, cannot short, and is reading CSRC guidance notes rather than MSCI rebalancing schedules).

So the July 20 T+1 optimization HKEX's Market Operations Division has scheduled lands in a market that is structurally bifurcated in ways the settlement cycle alone cannot fix. The PRC Southbound investor already settles on a compressed cycle through the Connect pipes; the T+1 shift matters most for the international institutional accounts that have been losing share of free-float since 2019, and whose remaining participation is now concentrated in the large-cap names with enough daily turnover to support real position management. The Chinese and Hong Kong listing share of global IPO proceeds reaching 22 percent in H1 2026, per this week's figures, is the number the exchange marketing deck will use; the number practitioners on the international side are watching is whether MSCI's August index review, which prices free-float and turnover data through June 30, finally moves the weight on any of the H1 debut names enough to bring passive flows back in size.