A ship owner makes an offer to a charterer or vice-versa, this is known as a firm offer. A very important aspect of the ethics of shipbroking is the treatment of firm offers. The code of ethics of the Baltic Exchange, of the Institute of Chartered Shipbrokers and of all other sensible shipbrokers prohibits the making or the holding of more than one firm offer at one time. When negotiating, it is not possible to hold two firm offers. When a shipbroker acting on behalf of the owner makes a firm offer, the ship cannot be offered elsewhere at the same time. Equally a charterer cannot make an offer to two ships at once, otherwise he could be obliged to provide two cargoes. All offers, therefore, have a time limit attached. It must be clear in what place (or time zone) the time limit is to apply, e.g. ‘10 pm Tokyo time’. This system has advantages for both owners and charterers, as each party knows that the other is interested in their business and that a contract or ‘fixture’ will follow, provided they can agree on all the terms. They also know that they are not in competition with another party, i.e. the owner knows that the charterer is not talking to another owner and the owner knows that his is the only ship which the charterer is fixing. It is possible to offer a ship or cargo subject open or subject unfixed, thus indicating that negotiations are being conducted with other parties. Many owners or charterers refuse to do business on this basis.