Tursab is the official governing body of travel agents in Turkey. So a travel agent showing the symbol and the number is a registered travel agent. It has been investigated by the ministry of tourism and provided all the necessary paperwork, certificates to show it is operating correctly. If it fails to operate responsibly this certification can be removed or it can be fined. It has not paid
up a bond as in the abta or atol system. It is graded according to what it does incoming or outgoing travel.
I hope this answers your question.

rwb47 thanks for that

So it is just a register for companys then.
Not a bond which protects us from travel agents going bust
when i see someone saying they were bonded by tursab a didnt realize it dont protect holidaymakers from losing money

TURSAB is nothing to do with holiday bonding anyone who says it has is a complete liar. It is the government regulation body controlling travel agencies in Turkey.
To obtain a TURSAB licence a company must meet a range of strict criteria including the provision of adequate insurance.
A class A agency are legally allowed to operate and sell their own tours, A class B agency can only sell tours on behalf of another company.
Therefore for peace of mind try to book tours with a class A agency as they will organise their own tours and so have complete control over what happens.
A class B agency can pass the buck if there is any problems!
Above is courtesy of sarikanarya.

Here's their website:- http://www.tursab.org.tr/content/english/home/