On Tuesday share index fell over 1.5 percent to hit a near two-week low by 8:16 a.m. British time due to profit taking after it hit a fresh record high on Monday. Analysts said the market had shrugged off Fonseka's court martial.
Fonseka and Rajapaksa worked together to end the war against the Tamil Tiger separatists last year but soon fell out.
Fonseka lost by an 18 percentage point margin to Rajapaksa in the January poll, after which he accused the president of rigging the vote.
(Editing by Sihar Aneez and Sanjeev Miglani)