Imported from previous forum
Field 18 (ExecInst) can take (amongst others) values A (No cross) and B (OK to cross). How should these fields be interpreted by the broker: does it strictly forbid to cross, or is crossing allowed in certain circumstances (a cross reported to the stock exchange within the spread using electronic interfaces could make no difference to the client, and is sometimes better for him, than a standard execution) ? What is the fundamental behind this flag ?