This empirical study is concerned with the usefulness of proposed supplementary disclosures for oil and gas producers to financial analysts in valuing a company. It is concerned with what supplementary information is being used, to what extent it is being used and which type of information is used most. Three main research procedures are employed. In the first procedure, the Mann-Whitney U Test is applied to determine any significant difference between valuing an oil and gas producing company using basic financial statements and ratio data, and valuing the same company with this information plus the proposed disclosures. The second procedure involves applying the chi-square and Cramer's V statistics to determine whether the disclosure information caused switching in valuation method used for each of the cases. The third procedure tests for significant differences between financial ratios used for each case by employing the test of differences between two proportions. Additional evaluation attempts to determine analysts' perceived usefulness of each of the schedules of the proposed disclosures