Ground rules of Index 9000

01Purpose and scope

Index 9000 measures the performance of the listed equity market of the world, held in proportion to its free-float market capitalisation and without interference. The index is designed to be the market rather than a view on it. This document sets out the rules by which the index is constructed, maintained and calculated. Where the rules are silent, no action is taken.

02Eligible universe

A security is eligible for inclusion if, at the review data date, all of the following are true.

1. It is a common equity share, or a depositary receipt over one, listed on a recognised exchange with continuous trading.
2. It has traded on at least ninety percent of trading days in the six months to the data date.
3. Its market capitalisation is available from the public feed on the review data date.
4. It is the primary listing of the company. Depositary receipts, secondary lines and cross-listings are excluded; where a company is listed in several places, the line with the greatest turnover is taken.

Where a company has more than one eligible share class, each class is treated as a separate security and ranked on its own free-float capitalisation.

03Constituent selection

At each annual review the eligible universe is ranked by market capitalisation in US dollars. The index comprises the 9,000 highest-ranked securities, subject to the buffer in 3.2.

1. A security not already in the index is added if it ranks 8,100 or higher.
2. An existing constituent is retained if it ranks 9,900 or higher, and removed if it ranks below 9,900.
3. If the application of 3.1 and 3.2 leaves the index with more or fewer than 9,000 securities, the difference is made up from the ranking, lowest-ranked retained constituents being removed or highest-ranked non-constituents added, until the count is 9,000.

Between reviews, the constituent count may fall below 9,000 through removals under section 6. It is not restored until the next review.

04Weighting

Each constituent is weighted by its market capitalisation: price multiplied by shares in issue, converted to US dollars. No free-float adjustment is made, no cap is applied to any constituent, sector or market, and no constituent is weighted other than by its capitalisation.

Weights change with every price. Share counts are fixed at the annual review as capitalisation divided by price on the review data date, and change only on corporate actions under section 6.

05Annual review

The index is reviewed once a year. Data are taken as at the close of the last business day of August. Changes take effect after the close on the third Friday of September and are announced no later than the first business day of September.

The review updates constituents under section 3, and share counts and free-float factors for all constituents. There is no interim review and no provision for one.

06Corporate actions

Between reviews the following events are reflected, on their effective date, so that the event itself neither adds to nor subtracts from the index level.

1. Share splits and consolidations. Shares in issue are adjusted by the split ratio. The divisor is unchanged.
2. Rights issues. Shares in issue are increased by the shares offered, and the price is adjusted for the theoretical ex-rights value. The divisor is adjusted so that the level is unchanged.
3. Delisting and insolvency. The security is removed at its last traded price on the exchange from which it is delisted. Where no traded price is available it is removed at zero. Removal does not trigger an addition.
4. Mergers and acquisitions. Where the acquirer is a constituent, the acquired security is removed and the acquirer's shares in issue are adjusted for shares issued as consideration. Where the acquirer is not a constituent, the acquired security is removed at the offer terms and nothing is added.
5. Spin-offs. The spun-off entity is added at its first traded price with the parent's free-float factor, and is retained until the next review, at which it is treated as any other security.
6. Prolonged suspension. A constituent suspended from trading for twenty consecutive trading days is removed at zero on the twenty-first day. If trading resumes it is eligible again from the next review.

No other event is reflected. In particular, changes in shares in issue arising from buybacks, option exercise and placings are reflected only at the annual review.

07Calculation

The index is a total-return index: dividends are reinvested, so the level measures what holding the whole listed world would have returned, not merely what its prices did. It is calculated every three minutes from the latest price on the primary listing of each constituent, and once a day at 22:15 UTC, after the last constituent market has closed, as the official close.

where p is the latest price, s the index shares, f the free-float factor (fixed at 1 since version 1.5), x the live exchange rate to US dollars, and D the divisor. The divisor is set at inception so that the level is 1,000.00 and is adjusted under section 6 so that corporate actions and constituent changes do not themselves move the level.

On a constituent's ex-dividend date the cash dividend, multiplied by its index shares and converted to US dollars, is treated as reinvested across the whole index: the divisor is reduced in the proportion of that cash to the index's value, so the level is unaffected by the price falling ex-dividend. Dividends are applied at the official close of the ex-date, or of the first close after the feed reports them. A dividend greater than half the share price is treated as a data fault and recorded in a notice.

Where a constituent has not traded on day t, its last traded price is carried. Where an exchange is closed, all of its constituents are carried. The level is published to two decimal places.

08Base and history

The base level of 1,000.00 was set at the close of 31 December 1976. The record to 18 September 2026 is a back-history computed from real market data on a total-return basis: the S&P 500 with its dividends to 1984, MSCI World and MSCI ACWI with dividends reinvested at the S&P 500's yield to mid-2008, and Vanguard's Total World Stock ETF (VT) with dividends reinvested to launch, each series chained to the next at the join and the whole rebased to 1,000.00 at 31 December 1976. From 19 September 2026 the index is calculated from its own constituents, with the divisor set on that day so that the level continued the back-history at 146,061.16. Historical levels are never restated; a correction to an input after publication is reflected in the next level through the divisor.

The full monthly record is published on the History page.

09Governance

The index is administered by Robinhood. There is no index committee. The rulebook is applied as written and provides for no discretion; where a situation arises that the rules do not cover, no action is taken, and the situation is recorded in a notice.

Revisions to this document are limited to corrections and clarifications. A revision that would change which securities the index holds, or how much of each, is not a revision but a different index, and is outside the scope of this document.

10Definitions

Index shares

Market capitalisation divided by price on the review data date, held fixed until the next review or a corporate action.

Market capitalisation

Price multiplied by shares in issue, in US dollars at the live exchange rate.

Recognised exchange

An exchange with a published rulebook, a central order book and settlement within three business days.

Review data date

The close of the last business day of August.

Trading day

A day on which the security's primary exchange is open for continuous trading.

11Data sources

Constituent lists, market capitalisations, prices and exchange rates are taken from public exchange feeds. Prices are real time or delayed by fifteen to twenty minutes according to the exchange. A constituent whose feed does not update is carried at its last price under section 7. Markets with no public feed are not carried; as at version 1.5 these are Egypt, Peru and the Philippines.

The four series of the back-history (section 8) are taken from the same source, with the S&P 500's monthly dividends from a published academic series. Dividends for constituents are taken from the feed's corporate-action records.

The feed is a convenience, not an authority. Where it is plainly wrong, the constituent is carried at its last good price and the fault is recorded in a notice.

12Version history