Singapore Bus Services' corporate history

Scania SG

As many would know, Singapore Bus services was formed when 3 Chinese Bus companies (Which were formed in 1970 in another earlier government sanctioned merger, the three are Amalgamated Bus Company, United Bus Company and Asscociated Bus Services) were forced by the government to form a new bus company so as to provide better bus services in Singapore. This uneasy and volatile merger gave rise to the government sanctioned Singapore Bus Services. In 1978, Singapore Bus Services was lised on the stock exchange of Singapore (that time still don't have the name SGX)

Question 1
Was SBS a government owned bus company/entity/statutory board (like MRTC, then Singapore Mass Rapid Transit, now SMRT Corp)? i) if it was, when was it privatized?

SBS then ventured into more areas of business (SABS, SBS Taxi). In 1992, another separate entity was formed, Singapore Bus Services Ltd, this became the subsidary of SBS (1978) Ltd

Question 2
Was Singapore Bus Service Ltd listed on the stock exchange like SBS (1978) Ltd

Question 3
Did the other buisness areas (SBS Taxis, SBS Leisure and SBS Properties) also got registered as separate entities like Singapore Bus Services at the same time, or did they get it later than the Singapore bus business.

Question 4
Did Trans Island go through the same process of registering different business areas into different companies or TIBS Holdings just pop up in the first place?

And of course, in 1997, Singapore Bus Services (1978) Ltd became Delgro Ltd. In 2001, subsidary Singapore Bus Services Ltd was renamed as SBS Transit Ltd and in 2003 Delgro merged with Comfort Transportation to form ComfortDelgro.

If you have any constructive knowledge on the above questions, please help to answer the missing parts.

This is about corporate history, not bus fleet or deployment.