At 12.30pm, the FBM KLCI was down 2.83 points to 1,635.18. Trading volume was 2.22 billion shares valued at RM1.26bil.
There were 414 decliners versus 329 gainers and 401 counters unchanged.
Tenaga Nasional weighed on the index with a 18 sen fall to RM12.16 to return to Monday's closing price while IHH dropped 10 sen to RM5.51, erasing its gains over the previous session.
CIMB also saw selling pressure, losing six sen to RM5.19 alongside Hong Leong Bank, which gave up four sen to RM19.98.
Among the highlights of the morning, Genting picked up 19 sen to RM7.04, extending its advance for a fifth straight session while Axiata rose four sen to RM3.97.
Top active stocks included Bumi Armada, which slipped back 2.5 sen to 24.5 sen following a strong advance yesterday on news that it had secured refinancing for its corporate debt.
Kenanga research maintained its underperform rating on the stock, stressing that the group's high net gearing remains a concern.
"This still does not mitigate the company’s high level of borrowings, amounting to RM10.4b as at end-FY18 - implying an alarming net-gearing level of 2.7x," Kenanga said of the refinancing.
Ekovest maintained a positive performance, putting on five sen to 98.5 sen while IWCity rose three sen to RM1.22. The two counters have seen some see-sawing during the course of the week on news of the revival of the Bandar Malaysia project and speculation over potential benefits.
Bursa's top gainer by percentage terms was G3 Global, whose price was en route to a third straight day of gains, picking up 23 sen or 21.5% to a historical high of RM1.30.
At the close of the Thursday morning session, the stock has put on 48 sen or 60% of its value since last Friday.
Meanwhile, regional markets were generally weaker given a surprise deterioration in German and South Korean economic data that renewed fears of slowing global growth.
Crude oil prices, which have been on a tear following the US decision to end its sanction waivers for countries importing oil from Iran, stayed firm near six-month highs.
US crude fell nine cent sto US$65.81 a barrel and Brent crude rose three cents to US$74.60 a barrel.
In currencies, the ringgit slipped 0.15% against the greenback to 4.1350 while it rose 0.1% against the pound sterling to 5.3355 and 0.15% against the Singapore dollar at 3.0350.