The New China Index That Refuses to Own the Expensive Share

An index is not a thing. It is a rule for choosing things, and most of the rules are boring — buy the biggest companies, weight by size, rebalance every so often. Hong Kong's newest China index has a rule that is not boring, and the difference is the story.

The odd part about the headline number is who is behind it. Last November, Hong Kong Exchanges and Clearing — the company that runs the Hong Kong stock market — put its own name on an index for the first time. It is the Hang Seng HKEX Stock Connect China Enterprises Index, a name so long it trades on the acronym SCCEA, and it tracks the 80 largest Chinese companies whose shares are reachable through Stock Connect, the plumbing that lets investors in Hong Kong, Shanghai and Shenzhen buy each other's markets. It launched on 21 November 2024. So the "plans to launch" version of the news was stale before it finished being written; the benchmark is already live and already being marketed as a product.

Here is the rule that makes it interesting. Tons of big Chinese companies are listed twice at once: once in Shanghai or Shenzhen as an A-share, and once in Hong Kong as an H-share, for the same underlying company. The two share classes trade at different prices, and the A-share almost always costs more — the famous "A/H premium," global investors' price for not being able to get the cheap version. The SCCEA has a rule about that. When a constituent's A-share is trading at a premium of more than 3% over its H-share, the index switches the A-share class to the H-share class. Since the premium is usually well above that, the practical effect is that the index keeps defaulting to whichever version of the company is cheaper and refuses to pay the A-share markup.

That is weird, and the basic point is that it is a feature, not an accident. An index with that rule is a selling document — it is essentially promising that this is the China benchmark the investor would have wanted all along, the one that holds A-shares when they are reasonable and quietly steps over to the cheaper Hong Kong line when they are not. It is also, implicitly, an advertisement for Stock Connect itself: the whole point of the link is that investors no longer have to hold the expensive class, because the cheap one is now just a trade away.

Which brings up the actual question of why a stock exchange, which is basically a toll booth, would bother co-branding an index at all. The reason is that indices are the raw material of trading volume. A benchmark like this gets packaged into exchange-traded funds and, potentially, into futures and options; every one of those products is a stream of trades, and every trade is a toll the exchange collects. Hang Seng Indexes normally owns and runs the old China benchmark, the Hang Seng China Enterprises Index, on its own. For HKEX to put its own name on the new one next to Hang Seng's is a way to claim a slice of the category-defining franchise — to be the entity that decides what "China" means as an investable asset class, and then to collect fees on every derivative and fund built around that definition. HKEX intends to work with asset managers, issuers and market participants on new product innovations based on the index, which is exchange-speak for "we are going to try to make this the thing you trade."

The timing is the telling part, because it points at why HKEX wants this benchmark to belong to it. Stock Connect's numbers have exploded. In 2025, northbound turnover (global money buying mainland A-shares through Hong Kong) averaged RMB 212 billion a day, up 42% from a year earlier,and southbound turnover (mainland money buying Hong Kong stocks) more than doubled to a record HK$121 billion a day, so that by the fourth quarter mainland investors were nearly a quarter of the Hong Kong cash market. Northbound Stock Connect trading fees rose 44% on the year. The mainland has been moving its own share of the action: mainland companies raised a record amount on the A-share markets, then increasingly came to Hong Kong for a second, "A-to-H" listing to reach international money — 19 such deals worth US$17.7 billion in 2025.Hong Kong's total equity capital markets raising hit a record US$103 billion, up 164%.

This is the machine the index is trying to help run. Hong Kong is no longer just the place where Chinese companies get their primary listing; increasingly it is the wrapper that lets global investors own Chinese companies that list back home on the mainland. An index that holds both the Hong Kong and the mainland versions, and cheerfully picks the cheaper one, is a single ticker for the whole China trade — one that happens to route every trade through Hong Kong's toll booth.

For an ordinary investor, there are two honest readings, and they are different sizes. As a China-exposure product, the SCCEA is genuinely clever: a one-stop way to own the China market at, most of the time, the cheaper of the two share classes — the A/H discount becomes something the index captures instead of something the investor pays. Whether a fund tracking it actually shows up, and at what fee, is the thing to watch; an index nobody builds a product on is just a clever spreadsheet.

As a reason to own HKEX's own stock (it trades under 0388.HK), one index is a rounding error in the earnings. The exchange's economics are a reflection of turnover, so the real variable is not this benchmark but the Connect flow that has been driving it. The index is not a new earnings line; it is a symptom of a larger wager that Hong Kong, not the mainland list, should be where the world buys China. Own the stock for the flow if you want to own it — not for the index.

The funniest thing about the whole structure is that it proves the discount it exploits. You only need a rule to refuse to pay the A-share premium because the premium keeps showing up. HKEX's answer to that is not to explain the gap away but to build a benchmark that walks around it, and then charge for the walking.