The main All Share Price Index was stagnant at 5,449.46, while the more liquid Milanka index rose 0.
51 percent (24.83) to close at 4,889.08.
Turnover was 3.1 billion rupees, according to stock exchange provisional figures.
A foreign investor bought a five percent stake in Aitken Spence, amounting to 20.5 million shares, from the Employees' Provident Fund, a state-managed retirement fund of private citizens.
The deal was done in three off-market deals totaling 2.36 billion rupees at 115 rupees a share.
Aitken Spence was the highest contributor to the daily turnover. Aitken Spence closed Monday at 116 rupees, up 80 cents.
The EPF on Friday had sold 71 million shares in another conglomerate, John Keells Holdings, to Malaysia's Khazanah Nasional Berhard.
John Keells Holdings closed Monday at 200 rupees, up 4.90 rupees.
Brokers Lanka Securities said foreign participation stood at 47.
4 percent of the total market activity with foreign investors being net buyers with a net foreign inflow of 2.5 billion rupees.