Stocks ticked higher in midday trading on Wednesday, just hours after a government shutdown began, defying fears among some observers about the economic risk posed by a potentially prolonged impasse.

The Dow Jones Industrial Average jumped 71 points, or 0.15%, while the S&P 500 jumped 0.1%. The tech-heavy Nasdaq increased 0.1%.

The uptick extended a period of resilient performance for markets, which shrugged off the looming impasse a day earlier. Each of the major indexes ticked up on Tuesday, including a record high for the Dow.

The shutdown coincides with a rough patch for the U.S. economy, at least by some key metrics. A recent hiring slowdown has stoked recession fears, while inflation has proven difficult to fully contain.

Fresh hiring data on Wednesday morning deepened concern about the labor market. Private sector employment declined by 32,000 jobs in September, registering well short of economists' expectations of 45,000 jobs added, according to data firm ADP research.

A government shutdown typically risks only modest damage for the U.S. economy, stemming mainly from furloughed public workers, who temporarily lose out on pay and put a dent in U.S. consumer spending, analysts previously told ABC News.

The impact of a shutdown could be more significant this time around, however, since the wobbly economy may strain under the weight of a potentially prolonged interruption, while a halt in the release of key economic data could make it more difficult for policymakers to steer the economy, they added.

This is a developing story. Please check back for updates.