The JSE extended its losses on Friday, taking its lead from edgy world markets as investors fretted over whether US President Donald Trump would be able to follow through on his pro-growth initiatives.
The all share index was off 0.43% to 51,804.50 points at midday, as resources in particular came under intense pressure.
"The ability of the Trump presidency to achieve legislative goals has moved centre stage in the markets overall psychology, " Momentum SP Reid Securities analysts said in a note.
"In large measure, the rally of the past few months has emerged in the wake of the pro-growth ... agenda of the new administration."
The local share market also laboured under a very strong rand, which some analysts think is going to be a recurring theme in the coming months.
The all share is heavily dominated by companies that derive most of their income overseas, making it sensitive to currency movements.
The rand was headed for hefty back-to-back weekly gains to the dollar, supported by improving local data and a weaker dollar.
Europe‚Äôs leading markets were moderately weaker, as were US stock futures following the postponement of the vote on the US healthcare bill to later on Friday. A failure to clear this hurdle would undermine the markets belief surrounding fiscal and taxation initiatives, a development that would undermine overall market sentiment, Momentum analysts added.
Among some individual shares, global commodities trader and miner Glencore was off 2.48% to R49.90, with Anglo American slipping 1.63% to R195.30. ArcelorMittal gained 2.11% to R11.15.
Anglo American Platinum was off 4.45% to R275.18, with Impala Platinum losing 3.01% to R41.85.
Financial services group Discovery lost 1.14% to R134.96 while Anchor Capital rose 4.62% to R7.70.