Introduction
A good corporate governance is important
for the listed companies because it signifies
effectiveness and transparency of the executives,
leading more confi dence to shareholders, investors
and managerial stakeholders. In 2002, the Stock
Exchange of Thailand (SET) began its campaign
to stimulate the companies listed on the Stock
Exchange of Thailand to realize importance of
good corporate governance by introducing its 15
principles, and later on, in 2004, good principles
of corporate governance had been improved
to conform with those of OECD (Principles of
Corporate Governance of OECD, 2004) Apart
from these, the Stock Exchange of Thailand tried
to support continuously not only for accepting
and bringing corporate governance into practice
effectively in the groups of listed companies
but also for bringing it into improvement for the
corporate governance of today. Its supporting
objectives of the Stock Exchange of Thailand were
to raise the level of listed companies of Thailand
able to stand rival to many international ones in
increase of their competitive abilities as a growth
promotion of the Stock Exchange of Thailand
and in conformity to the regulations of corporate
governance assessment of ASEAN (ASEAN CG) that
was a tool of estimating the level of corporate
governance of those companies listed in ASEAN
and had been brought in use in the middle of
ASEAN member countries since 2012. (http:/www.
set.or.th)
From the National Economic and Social
Development Plan, 11th issue (2012–2016), the
National Economic and Social Development Board
aimed at adaptation importance of Thailand to
multi-central global economies that Newly
Industrialized Countries (NICs) in this region, such
as Hong Kong, South Korea, Singapore, Taiwan and
some member countries in ASEAN paid important