The BidRequest Message can be used in one of two ways depending on which market conventions are being followed.
In the 'Non disclosed' convention (e.g. US/European model) the BidRequest message can be used to request a bid based on the sector, country, index and liquidity information contained within the message itself. In the 'Non disclosed' convention the entry repeating group is used to define liquidity of the program. See "Program/Basket/List Trading" for an example.
In the 'Disclosed' convention (e.g. Japanese model) the BidRequest message can be used to request bids based on the ListOrderDetail messages sent in advance of BidRequest message. In the 'Disclosed' convention the list repeating group is used to define which ListOrderDetail messages a bid is being sort for and the directions of the required bids.
The pair of fields SideValue1 <396> and SideValue2 <397> are used to show the monetary total value in either direction (buy or sell) of the transaction without revealing whether it is the buy-side institutions intention to buy or sell.
The two repeating groups, NoEntries and NoBidComponents <420> are mutually exclusive and a function of which bidding model is being used. If the 'Non Disclosure' method is being used the portfolio of stocks being traded is described by a number of 'bid descriptors' entries. If the 'Disclosure' Method is being used the portfolio is fully disclosed, except for side, by a number of 'list' entries enumerating the lists that list the stocks to be traded.
A BidRequest message with BidRequestTransType <374> cancel may be used to indicate to sell side firms that they no longer need to store details of the BidRequest as they have either lost the bid or the List has been canceled.