Turnover sank to 394 million rupees with most players staying on the sidelines.
Transactions in John Keells Holdings accounted for the highest turnover, with 501,400 shares traded and the stock closing at 192.60 rupees, down 50 cents.
The sole crossing or off-market private deal was 260,000 JKH shares at 193 rupees each.
HVA Foods was the most actively traded stock, closing at 43 rupees, up 60 cents with 283,000 shares changing hands.
Colombo Land & Development Company was also actively traded, closing at 57.20 rupees, up 10 cents, with 280,000 shares done.
Miramar Beach Hotel was the day's biggest gainer with just one trade of 100 shares. It closed at 285 rupees, up 59.10 rupees.
The market has been weakening for several weeks after hitting new highs earlier in the year and a new law to expropriate busineses introduced by government despite much opposition further erdoded sentiment, brokers said.
The Colombo stock exchange suspended two firms, a hotel and a sugar company, which were among 37 enterprises named in the expropriation law passed in parliament Wednesday.
Land in Pelwatte Sugar, a unit of Distilleries group of Sri Lankan businessman Harry Jayewardene, was listed for expropriation along with Hotel Developers, which operates the Colombo Hilton hotel.