Adam Posen, president of the Desen Institute for International Economics and a former Bank of England policymaker, said the shutdown itself and the turmoil surrounding the Bureau of Labor Statistics "have heightened widespread doubts about U.S. governance and reliability... That's important. It ultimately affects reserve management and monetary policymaking, and it affects the outlook for volatility in the U.S. that didn't exist before."

With major gaps in the flow of data covering about a quarter of global economic output, the outlook will become more uncertain the longer the shutdown lasts.

“Certainly, there is still a wealth of information out there, and policymakers are investing considerable effort in gathering microdata and anecdotal evidence on the U.S.,” said Robert Kahn, head of global macro at Eurasia Group. “But how best to integrate it all, and importantly, how markets will react to this news, are key unknowns. As time goes by, uncertainty accumulates and the risk of being wrong rises.”