NTT Communications bought into SLT as part of a privatization exercises paying 225 million dollars a decade ago.
"That means NTT makes a capital gain of 75 million dollars after 10 years," Arjuna Dassanayake from DFCC Stockbrokers, the selling broker of the deal said.
The DFCC was also involved in taking SLT public in the second stage of the privatization.
The buying brokers were CT Smith.
The deal was the largest in Sri Lanka's stock exchange history. Turnover of 32.5 billion rupees on Tuesday is the highest after 6.7 billion rupees recorded on 17 May, 2007 on a Dialog Telekom deal, traders said.
SLT shares rose 6.75 to 48.00 rupee after the deal was announced.
Expectations of a purchase by the UT group drove the share price to around 40 rupees but with no disclosure about the sale date or the size of the