NEW YORK (AFP) - Wall Street stocks edged higher on Wednesday (Oct 4) following strong US services-sector data, as all three major equity indices finished at all-time peaks for the third day running.

Data from the Institute for Supply Management showed growth in the US services sector hit a 12-year high, adding to positive sentiment ahead of third-quarter earnings reports and as Washington begins to made headway on tax cut policy.

"There is certainly no sign in these data of the economy weakening," said Jim O'Sullivan, chief US economist at High Frequency Economics. "Indeed, they suggest strengthening."

The Dow Jones Industrial Average added 0.1 per cent at 22,661.64.

The broad-based S&P 500 gained 0.1 per cent to 2,537.74, while the tech-rich Nasdaq Composite Index advanced less than 0.1 per cent to 6,534.63.

Earlier, payrolls firm ADP reported that private employment rose by 135,000 in September, lower than analysts' expectations, as hurricanes that devastated parts of the US weighed on hiring, private payrolls firm ADP said. The report comes ahead of Friday's more closely-watched government employment data.

Apple lost 0.7 per cent after the European Union filed suit against Ireland over an alleged sweetheart tax deal to the US tech giant.

But Amazon rose 0.9 per cent following an order from the EU that the online retailer pay Luxembourg €250 million (S$400 million) in back taxes.

Mylan surged 16.2 per cent after announcing that the US Food and Drug Administration approved a generic version of multiple sclerosis drug Copaxone, which had been under patent by rival Teva. Teva dived 14.6 per cent.