The deal, Southeast Asia's largest block trade in 2019, sent Intouch shares down nearly 6% on Thursday in Bangkok trading. Intouch shares, however, gained 27% year-to-date against a benchmark rise of 3.55%; stock was priced at 60.75 baht on Thursday at a pre-close of 64.5 baht.
Intouch did not immediately respond to a Reuters request for comment.
Former Prime Minister Thaksin Shinawatra sold InTouch, then known as Shin Corp, to Temasek in 2006, setting off public criticism that led to his ousting in a coup.
SingTel currently owns 21% of InTouch.
Credit Suisse was one of the book-runners.