Following yesterday's advance, the key index once again saw profit-taking, losing 5.61 points to 1,602.64 by midday.
Stocks on the 30-counter FBM KLCI were mostly lower with leading heavyweights in the red.
Among plantations counters, Kuala Lumpur Kepong dropped 32 sen to RM22.08, and Sime Darby Plantation dipped two sen to RM4.51.
In the financial sector, Maybank fell two sen to RM8.28, Public Bank lost two sen to RM4.21 while Hong Leong Bank rose four sen to RM17.98 and CIMB added one sen to RM4.31.
Glove counters were seen firming up after a morning decline, with Top Glove adding four sen to RM5.48 and Supermax climbing 11 sne to RM5.21. Hartalega was down one sen to RM9.99.
Among the leading gainers on the broader market, Transocean surged 35 sen to RM1.53, Amtel rose 19 sen to RM1.19 and Heineken added 16 sen to RM24.96.
Semiconductor player MPI was down 32 sen to RM38.98 and KESM lost 16 sen to RM12.08.
Elsewhere, positive US economic data coupled with a strong start to the earnings season helped to underpin a rally in global equities.
Japan's Nikkei was up 0.1% while South Korea's Kospi dipped 0.1%.
China's composite index rose 0.5%. Hong Kong's Hang Seng and Australia's ASX200 were mostly flat.