Why don't you and your family declare every cent you have to the whole world? Even communist North Korea and Democratic USA don't do that.
Similarly, a stock analyst making a public report on a public listed company is required by law to make a disclosure on his/her vested interest in that company.
This is to prevent biasness in the report which could potentially affect the stock price and the analyst benefit financially from the report.
Company laws also require directors to make a declaration if a contract is awarded to a company in which the directors have a vested interest in the beneficiary company. This is ensure transparency.
As office holders, the ministers have lots of insider information which he or she could easily benefit financially from the information. How do we safe guard public interest? Talk is cheap. Show us the money! Make a declaration.
Another example for you myo539:
Taksin changed some laws when he was PM of Thailand. The new laws benefited his telco company. Now his opponents cry foul and forced him out of office. A classical example of conflict of interest.
