Editor’s note: This is general educational information about how equity index sectors are assigned, not investment advice, and it does not comment on any company’s valuation. It is based on the official documents listed at the end.
A company does not choose its sector. Neither does the exchange it trades on. For South African equities the classification comes from the Industry Classification Benchmark, a rulebook maintained by FTSE Russell, and the input it reads is the company’s own audited segment revenue. That is why a business everyone calls an energy company can end up somewhere else on an index screen, and why the reclassification arrives on a fixed Monday four times a year rather than on the day the business changed.
Revenue decides, and the audited accounts are the source
ICB is a four-level structure for sector and industry analysis, running from industry down to subsector, and it allocates a company to the subsector whose definition most closely coincides with the source of its revenue, or of the majority of its revenue. Rule 4.2.1 names the evidence: the principal source of information is the company’s audited accounts and directors’ report. Where a company runs two or more substantially different lines of business, FTSE Russell bases the decision on the accounting segmentation published in those audited accounts. Interim statements are not normally used.
Only where revenue information is unavailable or insufficient, or where a company is new or changing its line of business, does the rulebook fall back to descriptions. The order is specific: the business description in the annual report, then the listing prospectus or regulatory filings, then the company’s website. Segmental reporting normally discloses revenue before tax, minority interests, extraordinary items and interest, and those items are disregarded in assessing sources of revenue unless there is audited evidence that they attach to a disclosed class of business. Interest counts where earning or incurring it is central to the business.
The allocation itself runs as a decision tree. Step 1 asks whether the company is a collective investment scheme or a diversified financial holding company. Step 2 asks whether it reports 50% or greater of revenue from one subsector. Step 3 asks whether revenue in one subsector is at least 20% larger than the next largest subsector. Step 4 asks whether the greatest portion of revenue comes from the banking subsector and the company holds a banking licence. Step 5 asks whether 50% or greater of revenue comes from one sector or industry.
Sasol’s 2023 annual financial statements show what that tree actually reads. The group reports six main reportable segments reflecting the structure the chief executive uses to make operating decisions: Mining, Gas and Fuels in the energy business, and Africa, America and Eurasia in the chemicals business. External turnover for the year was R289 696 million in total, of which Fuels contributed R116 235 million, Africa R67 772 million, Eurasia R47 577 million, America R44 492 million, Gas R7 234 million and Mining R6 386 million. No single segment reaches half the total, which is the situation Steps 3 and 5 exist to resolve.
The calendar, not the news
Classification changes are dated events. Under Rule 4.3.3, an adjustment following a review takes effect on the Monday after the third Friday of March, June, September and December, and the cut-off for receipt of data or justification is the last business day of January, April, July and October. The same quarterly rhythm governs periodic reviews: every company in the ICB global universe is reviewed following receipt of its annual report, changes are implemented after the close on the third Friday of March, June, September and December, an indicative list of pending changes is announced on the first business day of each month, and confirmed changes are announced on the Wednesday following the first Friday of February, May, August and November, with revisions possible until the Friday two weeks before the effective date.
Corporate events are handled faster. An adjustment resulting from a change in a company’s classification following a corporate event is implemented concurrently with, or shortly after, the event itself. Where an incorrect classification was assigned at IPO, FTSE Russell reserves the right to update it with a minimum of two business days’ notice.
Structural change moves slowest of all. Any change to the ICB structure, whether at subsector, sector, supersector or industry level, requires a minimum of six months’ notice, is considered by the FTSE Russell Industry Classification Advisory Committee, and is based on long-term trends rather than what the committee considers temporary fluctuations. FTSE Russell also seeks to avoid maintaining sectors or subsectors that contain a single company. Governance sits above all of it: the advisory committee may recommend changes to the ground rules and the structure, for approval by the FTSE Russell Governance Board.
Why the label moves money
Sector classification is not just descriptive. It feeds index construction, and index construction determines what tracking funds hold. The FTSE Global Equity Index Series ground rules run their own screens on top of classification. Constituents are adjusted for free float and foreign ownership limits, and securities with a free float of 5% or below are excluded outright. Liquidity is tested semi-annually, in March and September, by calculating a security’s monthly median of daily trading volume. Securities assigned to certain surveillance segments are ineligible, and an existing constituent moved into one is normally deleted at the next quarterly review.
Analysis: the lag is the design, not a defect
The obvious complaint about this system is that it is slow. A company can announce a transformational disposal in February and keep its old sector label until the third Friday of June. That gap follows from the way the rulebook ranks its evidence. Audited segment revenue is used because it is audited; interim statements are excluded because they are not. A classification system built to move at the speed of announcements would be a classification system built on unaudited claims about what a business now is.
The second design choice is that revenue, not assets, market perception or self-description, is the test. That produces results that read oddly to a general reader and consistently to an analyst. A diversified group is placed by where its money actually comes from, which is why the Sasol segment table matters more to its classification than any description of the company. It also explains the 20% margin in Step 3: where no subsector reaches half of revenue, the rule needs a tie-break that is wide enough not to flip on small year-to-year movements.
What the framework establishes is a reproducible, dated and auditable allocation. Two analysts reading the same audited accounts against the same rulebook should reach the same subsector. What it does not establish is anything about the quality, risk or prospects of the business. A sector label is a statement about the composition of last year’s revenue, and it carries no view on whether that composition will hold.
The practical consequence sits at the point where classification meets index membership. Because a reclassification takes effect on a known date and because index screens on free float and liquidity are applied on their own semi-annual and quarterly calendars, the flows that follow a label change are scheduled rather than sudden. A reader watching for that would track the indicative list published on the first business day of each month, the confirmed announcement on the Wednesday following the first Friday of February, May, August or November, and the company’s next audited segment note, which is the document that will drive the review after it.
