The All Share Price Index closed at 4,243.54, down 0.33 percent (14.13 points) while the more liquid Milanka index fell 0.
62 percent (29.94 points) to close at 4,792.71.
Turnover was 1.3 billion rupees, according to stock exchange provisional figures.
"Market activity continued to remain high, but unlike the first quarter of the year, we see price movements both ways," said Nikita Tissera, manager - research at SC Securities.
"Despite the higher prices, we still see value in the overall market while the over-bought stocks have lost investor flavour over time.
"We also see tendencies of the investor appetite somewhat slipping away from the 'high caps' and move towards the 'mid' and the 'low caps'.
"
Brokers said a negotiated off-the-floor deal of 11 million shares of Janashakthi Insurance Company at 14 rupees a share dominated the day's trade.
Janashakthi Insurance Company closed flat at 14 rupees a share
There were six smaller deals or 'crossings; of Distilleries Company of about a million shares. The stock closed at 125 rupees, up 1.
25.
Ceylon Leather Products shares continued to rise on expectations of a rights issue or warrants.
The stock closed at 168.25 rupees, up 8.50.