O&G companies are required to keep a report of their oil and gas reserves, mostly focusing on the proven reserves (see proven reserves). The reserve report is for both internal company purposes as well as for the financial world, owners of contiguous territory and the general public. A key problem in structuring information about reserves is that relatively objective estimates of reservoir characteristics must be combined with subjective forecasts of project feasibility and commerciality, since for instance a proven reserve is only as it is nominated if the reserves can be brought to market economically. In its degree of disclosure of information the report should balance the requirement of shareholders to learn more about the underlying value of their investment against the requirement of the company to maintain a level of confidentiality to maintain its competitive edge (see also reserves disclosure)