Johannesburg - The JSE opened little changed on Wednesday, with the local bourse showing a positive bias despite news that Moody's Investors Service had put out a ratings watch on Spain early today.
A trader said commodities weakened, while the dollar strengthened.
Trading volumes are thin, the trader said.
By 09:21 local time the JSE all share index rose slightly by 0.10%, with platinum miners gaining 0.52% and resources adding 0.12%. But gold miners fell 0.15%. Financials were up 0.15%, and banks (-0.09%) and industrials (0.09%) were virtually flat.
The rand was bid at R6.84 to the dollar from R6.80 at the JSE's close on Tuesday. Gold was quoted at $1 390.36 a troy ounce from $1 393.60/oz at the JSE's previous close, while platinum was at $1 698.50 /oz from $1 695.50/oz before.
"The market has come under pressure on the back of the Spanish news," the trader said.
Moody's Investors Service placed Spain's Aa1 local and foreign currency government bond ratings on review for possible downgrade early on Wednesday.
It said the main triggers for placing the rating on review for possible downgrade were Spain's vulnerability to funding stress given its high refinancing needs in 2011; and a potential further increase in the public debt ratio should the cost of bank recapitalisation prove to be higher than expected so far, whether to meet higher-than-expected asset impairments or simply to retain the confidence of the wholesale markets.
Increased concerns over the ability of the Spanish government to achieve the required sustainable and structural improvement in general government finances given the limits of central government control over the regional governments' finances was another trigger.
Dow Jones Newswires reported that European stocks are set for a weaker start on Wednesday, after credit ratings agency Moody's announces it is putting Spain's debt rating on review.
Asian stock markets were mostly lower on Wednesday, with shares in Japan weighed by a report showing a weak outlook for the country's manufacturing sector.
Japan's Nikkei Stock Average was 0.07% lower, and Hong Kong's Hang Seng Index was last 1.61% weaker.
Trading volumes were generally thin across the region, suggesting that the selling pressure was mild, while losses were limited as Wednesday's gains on Wall Street and strong US retail sales data.
Some market watchers said the rise in US Treasury yields suggested investments will increasingly shift into riskier assets.