At midday, the Dow Jones Industrial Average rose 19.47 points, or 0.07 per cent, to 26,954.54. The S&P 500 increased 1.65 points, or 0.06 per cent, to 2,993.72. The Nasdaq Composite Index rallied 2.06 points, or 0.03 per cent, to 8,119.73, Xinhua news agency reported on Monday.
More than half of the 30 blue-chip stocks in the Dow traded higher around midday, with shares of McDonald's and Nike up nearly 1.4 per cent and nearly 1.3 per cent, leading the advancers.
Six of the 11 primary S&P 500 sectors traded lower around midday, with the health care sector down 0.4 per cent, leading the losers.
Shares of Exact Sciences rose over 5.6 per cent, after the US diagnostics company announced that it got green light from the US Food and Drug Administration for its noninvasive colorectal cancer screening test for eligible average-risk individuals ages 45 and older.
US manufacturing Purchasing Managers' Index (PMI) surged to 51.0 in September, up from 50.3 in August, hitting a five-month high, London-based global information provider IHS Markit reported on Monday.
"Although picking up slightly, the overall rate of growth in September remained among the weakest since 2016, commensurate with GDP rising in the third quarter at a subdued annualized rate of approximately 1.5 per cent," said Chris Williamson, chief business economist at HIS Markit, in a data release.
Germany's manufacturing PMI slumped to 41.4 in September, wildly down from 43.5 in August. The worrisome reading marked the lowest level since the global financial crisis.
"All the uncertainty around trade wars, the outlook for the car industry and Brexit are paralyzing order books, with September seeing the worst performance from the sector since the depths of the financial crisis in 2009," said IHS Markit's principal economist Phil Smith in another release.
What's worse, the IHS Markit Eurozone Composite PMI also tumbled to 50.4 in September, down from 51.9 in August, which signals "the weakest expansion of output across manufacturing and services since June 2013."
( With inputs from IANS )