20 percent (10.25 points) to close at 5,130.03.
Turnover was 2.14 billion rupees, according to stock exchange provisional figures.
"The market witnessed selling pressure with all stocks taking a fall and volumes continued to be thin," Sahani De Silva, research analyst at Bartleet Mallory Stockbroker said.
"We expect the market to bounce back in the coming days with investors looking at bargain hunting.
"
Investors took defensive positions to minimize losses, while 'penny' stocks continued to be heavily traded, brokers said.
Blue Diamonds Jewellery Worldwide, one of the most traded shares in the last few days closed at 6.25 rupees, down 1.00 with 3.6 million shares traded.
Muller and Phipps closed at 1.40 rupees, down 10 cents with 5.0 million shares traded, and Piramal Glass Ceylon closed at 2.
90 rupees, down 10 cents with 4.4 million shares changing hands.
Seylan Merchant Bank closed at 1.70 rupees, down 20 cents with 17.1 million shares changing hands, while its non-voting shares changed hands at 1.
40 rupees, down 20 cents with 6.23 million shares traded.
Sierra Cables closed at 3.80 rupees, down 10 cents with 10 million shares traded, brokers said.
Gains on selected midcap and high value stocks stopped the market from falling further, brokers said.
In a privately negotiated off-the-floor deal 2.
2 million shares of Commercial Bank of Ceylon, an index heavy stock changed hands at 182 rupees per share. It closed at 182.00 rupees, up 3.75.
Hatton National Bank closed at 273.
50 rupees, down 50 cents, Nations Trust Bank closed at 52.75 rupees, down 1.00, Sampath Bank closed at 343.25 rupees, down 3.75 and Seylan Bank closed flat at 75.
25 rupees.
In another private deal 15 million shares of Janashakthi Insurance changed hands at 15.00 rupees with a premium of 25 cents.
It closed at 15.25 rupees, up 50 cents.
Kahawatte Plantations closed at 32.75 rupees, down 1.25 with 15.5 million of its rights shares changing hands at 2.00 rupees, brokers said.
Aitken Spence closed at 1,500.00 rupees, down 104.50 rupees on 100 shares traded, Hayleys closed at 303.
00 rupees, down 1.75 and John Keells Holdings, another index heavy stock closed at 201.
00 rupees, down 75 cents.