What is the TASI index?
TASI is the headline number for the Saudi market, the one quoted on the news when “the Saudi market rose today”. It is published by the Saudi Exchange, includes the eligible companies of the Main Market, and moves during the trading session, Sunday to Thursday; see Saudi stock market hours. Next to it the exchange calculates sector indexes, so you can see whether banks, materials or another sector led a move.
An index is a basket summarized as one number; it is not a stock you can buy directly. The stock market indexes lesson explains how indexes are built and compares TASI with the S&P 500 and others.
- TASI (Tadawul All Share Index)
- The main index of the Saudi Exchange: the companies of the Main Market weighted by free-float market cap, with each company capped at 15% of the index.
How is the TASI index calculated?
Each company counts by its free-float market cap: its share price × the number of its shares that are free to trade. Large holdings that are not expected to be sold, such as stakes held by government entities and other strategic owners, are left out. The index then moves with the total free-float value of all its members.
Free float can change a company’s weight more than its size does. In the drawing at the top of the page, hypothetical company A is worth SAR 1,000 billion but only 4% of its shares are free to trade, so the index counts 1,000 × 4% = SAR 40 billion. Company B is worth only SAR 120 billion, yet 60% of its shares trade, so it counts 120 × 60% = SAR 72 billion and weighs more than A. The market cap lesson covers free float in more detail.
- Free-float market cap
- Share price × the shares available to trade, leaving out large holdings such as government and strategic stakes. TASI weights its members by this value, not by total market cap.
What is the 15% cap in TASI, and why does Aramco weigh less than its size?
The Saudi Exchange added a 15% cap to TASI in December 2019, just before Saudi Aramco listed. If a company’s free-float weight would be above 15%, it is cut to 15% and the excess is spread over the other members, so the weights still add up to 100%. The caps are reviewed with the index’s quarterly maintenance. In the hypothetical drawing below, two companies at 24% and 16% are cut to 15%, and the other stocks go from 60% to 70% of the index.
Saudi Aramco is by far the largest Saudi company by market value, but the state owns the great majority of it, so only a small part of its shares is free float. Its TASI weight is therefore much smaller than its market value would suggest, so other heavyweights such as Al Rajhi Bank can matter as much to the index. The exact weights change with prices and are published by the exchange.
- Index cap
- A maximum weight any single member may have in an index. In TASI it is 15%; weight above the cap is redistributed to the other members.
Which companies and sectors are in TASI?
TASI holds companies from every sector of the Main Market: banks, materials such as petrochemicals, mining and cement, energy, telecoms, utilities, real estate, healthcare, food, retail, insurance and more. Banks and materials have long been among the heaviest sectors, so news about interest rates, credit growth and petrochemical prices tends to show up in the index.
The largest weights belong to a group of big banks and industrial and energy companies; Al Rajhi Bank has been among the very largest, and Saudi Aramco, SABIC, the Saudi National Bank and stc are among the familiar heavyweights. Because weights move every day, check the current list on the Saudi Exchange website rather than relying on a ranking from an article.
TASI vs MT30 vs Nomu: what is the difference?
MT30, the MSCI Tadawul 30 Index, was launched by MSCI and the Saudi Exchange in January 2019. It holds about 30 of the largest and most liquid Saudi stocks, between 25 and 35 at a time, weighted by free-float market cap with each stock capped at 15%, and it is rebalanced four times a year. It was built to be traded: the Saudi market’s first index futures, launched in August 2020, are based on it.
Nomu is not an index but a separate market. The parallel market opened in February 2017 for smaller companies, with lighter listing requirements than the Main Market, and it has its own index. Trading in it has been restricted to qualified investors, and the rules on who may trade have been under review, so check the current Saudi Exchange and Capital Market Authority rules. A Nomu company can move to the Main Market once it meets the Main Market requirements.
- MT30 (MSCI Tadawul 30 Index)
- An index of about 30 large, liquid Saudi stocks created by MSCI and the Saudi Exchange, capped at 15% per stock, and the basis of Saudi index futures.
- Nomu (parallel market)
- The Saudi Exchange’s second equity market, for smaller companies with lighter listing requirements, separate from the Main Market that TASI tracks.
How can you invest in the TASI index?
You cannot buy the index itself, but there are three general routes, each through a broker licensed by the Capital Market Authority. You can buy individual Main Market shares; you can buy funds and ETFs, listed in Saudi Arabia or abroad, that track a Saudi index such as TASI, MT30 or an MSCI Saudi index; and traders with access to the derivatives market can use MT30 index futures, which carry leverage and the risk of losing more than a small move suggests.
Saudi citizens and residents have long invested directly. Since February 1, 2026, the Capital Market Authority allows all categories of foreign investors to invest directly in the Main Market, without the earlier qualified foreign investor requirements, and it ended the swap arrangements that non-residents used for indirect exposure. Limits on foreign ownership in individual companies were kept when the market opened, so check the current rules. If you need Sharia-compliant exposure, see halal stock investing.