Stock market sector: meaning

What is a sector?

A sector is a group of listed companies whose main business falls in the same broad part of the economy, such as banking, energy or technology.

When people search for "sector wise stocks", they want companies sorted by these groups. Exchange market summaries, broker screens and annual reports use this sorting.

The formal definition

In equity markets, sectors come from a classification system. This is a fixed scheme that places each company in one category based on its main source of revenue. Two widely used global schemes are:

• GICS (Global Industry Classification Standard)
• ICB (Industry Classification Benchmark)

Both schemes are hierarchies. A sector is the broadest level. Below it sit industry groups, industries and sub-industries. So "sector" and "industry" are related but not the same: an industry is a narrower slice inside a sector.

Local exchanges often use their own sector lists. The Pakistan Stock Exchange, for example, groups listed companies into its own sectors in its market summaries. These lists do not always match GICS or ICB.

Worked example (hypothetical)

Imagine a small banking sector index made of a few banks. Each bank's weight depends on its free-float market value, meaning the value of the shares available for public trading.

• The largest bank has by far the biggest weight.
• On one day, the largest bank rises and the smaller banks fall slightly.
• The sector index still closes higher, because the large weight outweighs the small moves.

The lesson is that a sector index can rise even when most of its members fall. Before you read a sector move as broad strength, check how the index is weighted. For position-size or value sums, use the calculators page.

Where you see the term

• Market summaries: exchanges list quotes sector by sector, with volume and change per group.
• Trading platforms: watchlists and screeners can filter or sort symbols by sector. MetaTrader 5 groups symbols into folders, but those folders are set by each broker.
• Index pages: broad indices such as US100 or NAS100 are heavy in some sectors. This affects how they move. See stock indices.
• News and reports: phrases like "sector rotation", "sector weight" or "defensive sector" describe money moving between groups or the share of a fund held in each group.

Edge cases

• Conglomerates: a company with several businesses gets one sector, chosen by its main revenue. Its other activities are ignored.
• Reclassification: schemes are revised from time to time, and companies can move between sectors. Long-term charts of a sector may therefore mix different members.
• Labels vs. reality: some well-known internet companies are classed outside "technology", for example under consumer or communication sectors.
• Economic sectors: in economics, "sector" can also mean public vs. private sector. That is a different usage from the stock-market one.

In Pakistan, the regulator is the Securities and Exchange Commission of Pakistan (SECP), with trading in listed securities and commodities only via SECP-licensed securities and futures brokers. Trading CFDs on sector-heavy indices with leverage can lose money fast, so read about risk management first.

Related terms

• Asset class
• Blue chip
• Beta
• Free float
• Correlation coefficient
• Business cycle
• Exposure
• Fundamental analysis
• Trading glossary

Frequent questions

What is the sector meaning in the stock market?

It is the broad business group a listed company belongs to, assigned by a classification system.

Is a sector the same as an industry?

No. A sector is the wider group. Industries are narrower categories inside it.

Who decides a company's sector?

The provider of the classification scheme or the exchange decides, based mainly on the company's revenue sources.

Why do traders follow sector-wise stocks?

Companies in one sector often react to the same news, rates or costs. This helps traders read moves and check their exposure. It does not predict prices.