The main index ended down 0.11 percent, or 6.73 points, at 5,906.18, its lowest close since Oct. 23.
The day's turnover was 571.5 million rupees ($4.36 million), less than this year's daily average of about 865 million rupees.
Brokers said the market had not seen a surge despite a declining trend in interest rates after the central bank cut its policy rates to multi-year low last month.
They said the market would not see a sustained gaining trend unless retail investors return to the bourse.
The market has lost 0.78 percent since the central bank cut its key policy rates by 50 basis points on Oct. 15.
Shares in DFCC Bank PLC fell 3.09 percent to 119.20 rupees.
Foreign investors were net buyers of 294.6 million rupees worth of shares, extending the year-to-date net inflow to 23.56 billion rupees.
($1 = 131.1500 Sri Lanka rupees)
(Reporting by Ranga Sirilal and Shihar Aneez; Editing by Subhranshu Sahu)
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