As a result, in 1999, Thai listed companies were asked by SET to promote and build corporate
governance practices into their annual reports (Ratanajongkol et al., 2006). The practices included social and
environmental disclosures in corporate annual reports, but disclosure was voluntary so few listed companies
revealed social and environmental information in their annual reports. A revised version of the principle of
good corporate governance was published in 2006 (Lint, 2009) which suggested that board of directors should
set clear policy on social and environmental issues. Companies should disclose social and environmental
policies as well as the implementation conditions of such policies. As well, voluntary reporting was changed
to a “comply or explain” approach. The new principle has been used by Thai listed companies since 2007.
The new principle does not apply to environmental disclosures on Thai corporate websites so that web based
disclosures are still voluntary. Notably, Thailand is ranked 23rd in the world by number of users with internet
access (CIA, 2009).