Most exchanges charge fees for access to their real-time data. Market data vendors such as Thomson Reuters pass those fees down to their customers. If you want to be able to view real-time data from an exchange you need to request the subscription with your Eikon account entitlements and you'll be charged the exchange fee for access. The exchanges also typically have a policy, which makes the data non fee liable if it is delayed by a certain amount of time. In addition to real-time data Thomson Reuters also provides non fee liable (or reduced fee depending on the exchange rules) delayed data for exchanges that permit it. This delayed data resides in separate RICs prefixed with "/". When using Eikon COM APIs you subscribe to say TRI.N and your account is not entitled to view real-time data from NYSE the API automatically subscribes to the RIC "/TRI.N". If you're entitled to access this delayed RIC the subscription is established and the item status returned is RT_ITEM_DELAYED. For all intents and purposes this item status is equivalent to RT_ITEM_OK, except it signifies that the RIC you receive is not the RIC you asked for, but a delayed equivalent. The delayed data on Thomson Reuters datafeed is not just delayed, it is also heavily throttled. Delayed RICs are only updated at a max frequency of once a minute, which I guess is why you got an impression that you don't receive any updates for RICs with item status RT_ITEM_DELAYED. What RICs come back with items status RT_ITEM_DELAYED vs. RT_ITEM_OK should be consistent. It does not depend on the time of day. If you're entitled to real-time data you get RT_ITEM_OK. If you're only entitled to delayed data (or if you specifically request delayed RIC) you get RT_ITEM_DELAYED.