The main share index ended 0.22 percent, or 12.90 points, firmer at 5,909.95, its highest closing level since Aug. 27.
Foreign investors were net buyers of 329.6 million rupees ($2.51 million) worth of shares on Wednesday, extending the net buying so far this year to 21.07 billion rupees.
Leading fixed-line telephone operator Sri Lanka Telecom PLC rose 1.53 percent to 39.90 rupees, while top mobile phone operator Dialog Axiata rose 2.3 percent to 8.90 rupees.
Shares in market heavyweight Ceylon Tobacco Company PLC rose 2.91 percent to 1,147.60 rupees.
The day's turnover was 723 million rupees, well below this year's daily average of about 872 million rupees.
($1 = 131.2000 Sri Lanka rupees)
(Reporting by Ranga Sirilal and Shihar Aneez; Editing by Sunil Nair)
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