The term Regular Trading Hours (RTH) is generally used to refer to the primary trading session for a particular exchange or region. For example, in the case of US equity markets, the RTH are from 09:30 to 16:00 ET. This designation is relevant as many exchanges offer pre- and post-market trading sessions which are referred to as extended trading hours or trading outside of RTH.
As the majority of trading often takes place during RTH, it is considered the most liquid trading session. Clients who elect to trade outside of RTH should consider the following risks:
- Lack of Liquidity - There may be less trading volume during the extended trading hours relative to RTH due to fewer active buyers and sellers, This can make it more difficult for your orders to execute.
- Wider Spreads - Less trading volume during the extended trading hours may result in wider bid-ask spreads, again making it more difficult for your order to execute or execute at a price as favorable as that during RTH.
- Increased Volatility - Price fluctuations may be greater during the extended trading hours due to limited activity.
- Uncertain Prices - Prices during the extended trading hours may not reflect those during the prior RTH session or at the open of the following RTH session.
- Order Types - IBKR will generally not accept market orders during the extended trading hours.
You can check the details of a product, including the available trading hours, by right-clicking on its ticker row in TWS and selecting Financial Instrument Info followed by Description or Details. If you do not see these items, click on the arrow at the bottom of the menu to expand it and view all selections. You can also check the trading hours from the Product Listings page of the Interactive Brokers website.
As trading outside of RTH introduces special risks (See: Risks of After Hours Trading), orders will only operate within this time frame, by default, if the client specifically configures the order to execute outside RTH.
Additional Information