The results indicate that the main determinants of voluntary disclosure are the variables related with firm size, growth opportunities, organizational performance, board compensation and the presence of a large shareholder.

The research presents 8 factors affecting the level of voluntary information disclosure including: Firm size, Listed time, Profitability, Solvency, Separation of board of directors and executive director, Board size, Organizational ownership and Foreign ownership.

Three components were developed to measure the important level of voluntary disclosure: (1) establishing an item list of voluntary disclosure; (2) rating the important level of each disclosure item; and (3) the extent of the actual disclosure of these items.

According to the Financial Accounting Standards Board (FASB, 2001), the words ‘voluntary disclosure’ means disclosures particularly beyond the confines of financial statement that are not mandatorily demanded by generally accepted accounting principles (GAAP).