5 percent lower Monday amid foreign selling in some large cap stocks brokers said, as staff at the securities watchdog bid farewell to its chairperson.
John Keells Holdings fell 6.10 to close at 162.10 rupees with 4.5 million shares traded and Hatton National Bank fell 5.
0 rupees to 145.00 rupees with 3.0 million shares traded.
Distilleries Corporation, a cash rich Stassen's group company controlled by businessman Harry Jayewardene fell 1.
80 to 148.20 despite it increasing a stake in John Keells Holdings in recent days.
A source familiar with the group said it was 'seeking diversification'.
Pelwatte, a cane farming and sugar milling unit Distilleries is being expropriated by the state.
DFCC, another Stassen controlled bank last week bought a 9.
9 percent stake in Nations Trust Bank, a John Keells affiliate indicating a return of 'smart money' to the market.
Foreign investors sold 317 million rupees worth stock and bought 83 million rupees.
The benchmark Colombo All Share Index fell 91.9 points to 5,995.9 breaching a psychological 6,000 point barrier and the Milanka Index of more liquid stocks fell 1.
73 percent (90.63 points) to end at 5,155.95 points.
Turnover was 1.57 billion rupees.
Last week stocks rallied after brokers went to President Mahinda Rajapaksa over to force the regulator to relax credit rules and price curbs.
Chief executives or representatives of 24 brokers out of 27 attended the meeting, brokers said.
Staff at the Securities and Exchange Commission held a farewell party to Indrani Sugathadasa, a senior public servant who resigned saying she was upholding her principles, a rare event in Sri Lanka.
Among illiquid stocks that lost steam Monday was J L Morrison which closed 400 rupees down at 2,610 with just 200 shares traded, Colombo Pharmacy fell 81 rupees to close at 1,163 rupees.