The All Share Price Index eased 0.02 percent (0.34 points) to 2,155.19 while the more liquid Milanka edged up 0.07 percent (1.79 points) to 2,418.70, according to provisional figures.
Turnover was 131 million rupees.
Maskeliya Plantations was the most actively traded stock as well as the biggest in terms of volumes, followed by its parent Richard Peiris & Co.
Maskeliya closed up 15 percent or 4.50 at 34.50 rupees with over 1.6 million shares traded.
Richard Peiris ended up 6.70 percent or three rupees at 47.75 with 469,000 shares done.
"Today we saw retail investors attracted to Maskeliya Plantations mainly because of the takeover rumour," said Srimal Liyanage of Lanka Securities.
"If it's sold there'll be a material gain for Richard Pieris. So it went up."
He said the market is likely to remain "sluggish" in the near term in the absence of any market moving news or rumours that could affect the prices of individual stocks.
The suicide bomb attack in north-central Anuradhapura in which a general turned politician was killed along with over 20 others had no impact on the market.