Tadawul updates market order mechanism for TASI, Nomu

The Saudi Exchange (Tadawul) announced changes to the market order mechanism for the Main Market (TASI) and Nomu-Parallel Market, effective as of Oct. 4.

Under the new mechanism, market orders can be executed against available quantities across multiple price levels, within a maximum range of five price ticks starting from the best available price. Once that limit is reached, or no further quantity is available within the range, any unexecuted quantity will be converted into a limit order at the last execution price.

Previously, market orders were executed only against available quantity at the best price, with any unexecuted volumes converted into a limit order at the executed price.

Tadawul said the change is designed to increase the number of market orders that can be executed immediately by allowing access to additional liquidity within the five-tick range. As a result, a market order may be filled across several price levels rather than a single level.

The change applies only to securities listed on TASI and Nomu. The derivatives market will remain unchanged.

Example: Market order to sell 1,000 shares

Under the previous mechanism, if the best available price is SAR 10 for 100 shares, 100 shares are executed at SAR 10 and the remaining 900 shares are converted into a limit order at the same price.

Under the updated mechanism, the order continues to match against available quantities across multiple price levels.

The remaining 200 shares will be converted into a limited order at SAR 9.95; the last execution price. 

Market Order Mechanism