The All Share Price Index closed at 7,210.
09, down 0.42 percent (30.18 points) while the more liquid Milanka index was barely changed at 6,838.41, according to stock exchange provisional figures.
Turnover was 1.6 billion rupees.
There were nine deals of Colombo Pharmacy Company shares of 6,000 shares each amounting to 54,000 shares, all at 3,500 rupees a share, adding 189 million rupees to the day's turnover.
Colombo Pharmacy Company closed at 3,489.90 rupees, down 31.10 rupees with 84,600 shares traded altogether.
Environmental Resources Investments and fund manager Nimal Perera bought control of Colombo Pharmacy Company in September 2010.
Colombo Pharmacy has real estate holdings in key business areas in Union Place and Bambalapitiya in Colombo.
Sierra Cables was the most actively traded stock, as it had been on Friday, with the share closing at 5.50 rupees, down 40 cents with over 9.
2 million shares traded.
Guardian Capital Partners was also actively traded, closing at 266.
80 rupees, down 27.40 with 207,400 shares done
A stock exchange filing said Royal Ceramics Lanka, controlled by Dhammika Perera, bought 1,386,500 shares of LB Finance, which he also controls, at an average price of 188.89 rupees a share.