Sri Lanka's bourse edged up on Thursday for an 11th straight day with high trading volume on heavy retail and speculative buying while foreign investors were net buyers for the first time this year.

The main share index closed 0.1 percent or 7.03 points firmer at 7,021.88, its highest close since Oct. 4 after falling 1.5 percent in the early trade. It has gained 6.2 percent in the last 10 sessions, reported Reuters.

It has been Asia's best performer with a 5.8 percent gain so far in 2011 after being the top performer last year with a 96 percent return.

Foreign investors were net buyers for the first time in 11 sessions, buying a net 117.6 million rupees on Thursday. But they have sold a net 1.7 billion rupees' worth shares so far this year after selling a net 26.4 billion rupees last year, the Reuters further stated.