Hang Seng index series quarterly rebalance: HSI adds 3 constituents, expected to generate nearly US$11 billion in two-way passive flows

Overview

This report reviews the June 2026 quarterly rebalance of the Hang Seng index family and assesses the potential impact on the main indices, sector weights, passive flows, stock-specific trading, and Southbound Connect eligibility changes. The report covers HSI, HSCEI, HSTECH, and HSCI, focusing on index additions/removals, weight resets, free-float share changes, and the resulting passive buying and selling pressure.

Core views

The key view is that this Hang Seng index-family adjustment is sizeable and could generate nearly US$11 billion of total two-way passive flows. HSI will expand to 93 constituents, with only modest changes to the index's total market cap, valuation, and earnings-growth assumptions. By sector, Internet/Media & Entertainment and Health Care are expected to receive the largest passive buying, while Technology Hardware/Semiconductors, Energy, Banks, Insurance, and Financial Services may bear the heaviest outflows. At the stock level, Tencent may benefit from the higher weight cap, BeOne Medicines from inclusion in HSI, Baidu and NetEase from higher free-float factors, and Zhipu and MiniMax from inclusion in HSTECH; SMIC and Meituan may face pressure from lower weight caps, Kingdee and Kingsoft from removal from HSTECH, and CCB and AIA from mechanical weight adjustments.

Analysis framework

The report uses an index event-driven framework: first identifying the constituent changes announced by Hang Seng Indexes Company, then combining weight caps, free-float share counts, shares outstanding, and price bases to estimate post-rebalance index market cap, valuation, earnings growth, and potential passive flow; it then breaks the buy and sell pressure down at the sector and stock levels, and compares historical price performance and Southbound holdings around inclusion and removal events.

Methodology notes

• Index rebalancing analysisPassive flow estimation

  Estimate the amount passive funds need to buy or sell based on changes in index weights.

  The report combines constituent additions/removals, re-capping, free-float share changes, and shares outstanding changes to estimate potential passive net buying or selling at the index and stock levels.

• Event studyHistorical performance around additions/removals

  Compare stock relative performance before the announcement and around the effective date after the announcement.

  The report notes that historically, HSI and HSCEI additions usually outperform modestly after the announcement but may reverse near the effective date; HSTECH and HSCI additions are more likely to keep outperforming through the effective date.

• Stock Connect eligibility analysisSouthbound eligibility impact

  Changes in HSCI constituents may affect Southbound Connect investability eligibility.

  The report emphasizes that WVR stocks are subject to stricter listing-history, market-cap, and liquidity requirements; historically, Southbound holdings rose by about 1 percentage point two days after inclusion and by about 5 percentage points within three months, but share prices often rose before inclusion, then pulled back and stabilized afterward.

Asset mapping & comparison

Structured mapping from thesis to named assets (strengths, weaknesses, peers, risks).

• Hang Seng Index (HSI)

  Core coverage index; this rebalance adds 3 constituents and expands the index to 93 names.

  Strengths

  Index market cap is expected to rise to about US$2,150bn, and forward EPS growth is expected to improve from 11.3% to 11.6%.

  Weaknesses

  The rebalance involves a 3.4% weight adjustment, which may create short-term mechanical volatility at the constituent level.

  Comparison

  Compared with HSCEI and HSTECH, HSI's constituent-count change is more directly reflected as an expansion.

  Risks

  Trading between the announcement and the effective date may be front-run, and there is reversal risk around the effective date.

• Hang Seng China Enterprises Index (HSCEI)

  This rebalance replaces Sunny Optical and Haier Smart Home with Hansoh Pharma and Akeso.

  Strengths

  Index market cap is expected to rise to about US$1,410bn, and EPS CAGR is expected to edge up from 11.8% to 11.9%.

  Weaknesses

  The newly added names had materially underperformed before the announcement, so the short-term path may be volatile.

  Comparison

  HSCEI's rebalance weight is 2.8%, below HSTECH's 4.5% and HSI's 3.4%.

  Risks

  Historically, added names may initially adjust after the announcement and only recover after the effective date.

• Hang Seng TECH Index (HSTECH)

  MiniMax and Knowledge Atlas Tech (Zhipu) will replace Kingsoft and Kingdee.

  Strengths

  Historically, HSTECH additions have tended to keep outperforming through the effective date, and the new AI-related names may attract event-driven flows.

  Weaknesses

  Post-adjustment forward P/E falls from 18.6x to 18.3x, while EPS CAGR falls from 31.2% to 30.3%.

  Comparison

  HSTECH's rebalance weight is 4.5%, the highest among the three major indices shown in the report.

  Risks

  The removed names, Kingsoft and Kingdee, may face passive selling pressure, and the newly added names could see profit-taking after the effective date.

• Hang Seng Composite Index (HSCI) / Southbound eligibility

  Changes in HSCI constituents may trigger changes in Southbound Connect eligibility.

  Strengths

  Historically, Southbound holdings rise by about 1 percentage point two days after inclusion and by about 5 percentage points over three months.

  Weaknesses

  Share prices often rise before inclusion, then pull back and stabilize afterward, so chasing the move in the short term is risky.

  Comparison

  The Southbound eligibility effect comes not only from index passive flows but also from a change in the investable universe for Connect investors.

  Risks

  WVR stocks must meet stricter listing-history, market-cap, and liquidity requirements, so eligibility is subject to rule constraints and execution uncertainty.

• Internet/Media & Entertainment

  The report expects this sector to receive the largest passive buying.

  Strengths

  Potential passive net buying is about US$1.4bn, supported by Tencent's higher weight cap and higher free-float factors for Baidu and NetEase.

  Weaknesses

  The buying is driven mainly by index mechanics rather than a fundamental rating upgrade.

  Comparison

  Compared with other sectors, this sector is expected to see the largest inflow.

  Risks

  If flows are front-run, there may be profit-taking and price pullback around the effective date.

• Health Care

  The report expects this sector to receive relatively large passive buying.

  Strengths

  Potential passive buying is about US$850mn, supported by BeOne Medicines' inclusion in HSI and the HSCEI pharmaceutical substitutions.

  Weaknesses

  The benefit within the sector is concentrated in names that are added or see higher weights.

  Comparison

  The passive buying is smaller than in Internet/Media & Entertainment, but clearly better than the outflows expected in Technology Hardware/Semiconductors and the financial-related sectors.

  Risks

  Inclusion trading may cause short-term volatility, and fundamental risks are not addressed in this strategy report.

• Tech H/W & Semis, Energy, Banks, Insurance & Financial Services

  The report expects these to be the main sectors with passive outflows.

  Strengths

  If the sell pressure is absorbed and fundamentals remain unchanged, some names may present event-driven dislocation opportunities.

  Weaknesses

  Technology Hardware/Semiconductors are expected to see about US$1.0bn of outflows, while Energy, Banks, and Insurance & Financial Services are each expected to see about US$350mn to US$500mn of outflows.

  Comparison

  These sectors stand in contrast to Internet/Media & Entertainment and Health Care in terms of flow direction.

  Risks

  Passive selling, weight cuts, and eligibility changes may lead to continued short-term price pressure.

Key data

• Report date2026-05-24The page shows Portfolio Strategy Research, with time 24 May 2026 11:50AM HKT.
• Index adjustment announcement date2026-05-22Hang Seng Indexes Company announced the quarterly review results after the close on Friday, May 22.
• HSI constituent count90 -> 93BeOne Medicines, Aluminum Corp. of China, and J&T Global Express will be added to HSI.
• Adjusted weight shareHSI 3.4%; HSCEI 2.8%; HSTECH 4.5%This is the combined adjustment ratio after re-capping and free-float share / share count changes.
• Estimated total two-way passive flowsnearly US$11bnThe report estimates that all changes across the Hang Seng index family could together generate nearly US$11 billion of total buy and sell flows.
• Post-rebalance index market capHSI US$2,150bn; HSCEI US$1,410bn; HSTECH US$455bnThe corresponding changes are HSI +4.5%, HSCEI +2.3%, and HSTECH +3.4%.
• 12-month forward P/E changeHSI 11.1x -> 11.2x; HSCEI 10.1x -> 10.2x; HSTECH 18.6x -> 18.3xEstimated based on the post-adjustment index structure.
• 2026-2027 EPS CAGR changeHSI 11.3% -> 11.6%; HSCEI 11.8% -> 11.9%; HSTECH 31.2% -> 30.3%HSTECH growth moderates slightly after the adjustment, while HSI and HSCEI edge higher.
• Sector passive buyingInternet/Media & Entertainment +US$1.4bn; Health Care +about US$850mnThese are the sectors the report identifies as the largest potential passive buyers.
• Sector passive outflowsTech H/W & Semis about -US$1.0bn; Energy, Banks, Insurance & Financial Services about -US$350mn to -US$500mnThese are the main sectors the report identifies as potential outflow sectors.
• Historical holdings change after Southbound inclusion+1pp within two days; +5pp over three monthsThe chart indicates that Southbound holdings typically rise quickly after inclusion and continue to increase over the following three months.

Impact & implications

The investment implication is mainly short-term index-event trading and passive rebalance pressure. Stocks added, overweighted, or with higher free-float factors may be supported by expected flows before the effective date, but historical experience shows that some index additions reverse around the effective date. Stocks removed, underweighted, or dropped from Southbound eligibility may face passive selling and lower holdings. At the sector level, passive buying in Internet/Media & Entertainment and Health Care should support near-term liquidity, while Technology Hardware/Semiconductors, Energy, Banks, Insurance, and Financial Services face outflow pressure.

Risks

• The report is an index strategy study and does not constitute a single-stock fundamental rating or an independent buy/sell recommendation.
• Passive flow estimates depend on prices, free-float shares, index-tracked asset size, and actual execution arrangements, so the final flows may differ from the estimates.
• The main text and tables differ on the effective date, citing June 5 and June 6; the actual trading schedule should follow the official announcement from Hang Seng Indexes Company.
• Historical inclusion/removal performance does not guarantee future repetition, and it may fail especially in volatile markets, when flows are front-run, or when trades are crowded.
• Southbound Connect eligibility changes are constrained by listing history, market cap, liquidity, and WVR rules, so the actual eligibility outcome may differ from a simple index inclusion judgment.
• This report discloses that Goldman Sachs and its affiliates may have business relationships with covered companies, or potential conflicts of interest through holdings, market making, or trading.

What to watch

• Hang Seng Indexes Company's final implementation list, effective date, and post-close adjustment timing.
• Trading volume and relative performance around the effective date for HSI additions BeOne Medicines, Aluminum Corp. of China, and J&T Global Express.
• Passive flows and weight changes for the HSCEI replacements Hansoh Pharma, Akeso, Sunny Optical, and Haier Smart Home.
• Passive buy/sell pressure from the HSTECH additions MiniMax and Knowledge Atlas Tech (Zhipu) and the removals Kingsoft and Kingdee.
• Weight changes for Tencent, Baidu, NetEase, and others from the re-capping or free-float adjustments.
• Actual trading and price reactions in potential passive outflow names such as SMIC, Meituan, CCB, and AIA.
• The final impact of HSCI adjustments on Southbound Connect eligibility, and the change in Southbound holdings two days and three months after inclusion.
• Front-running before the effective date and reversal risk after the effective date, especially index-addition trades that historically outperformed after announcement but gave back gains near the effective date.