The nation's manufacturing sector contracted in January, reversing the prior month's expansion, a trade group said Thursday.

The Tempe, Ariz.-based Institute for Supply Management said its manufacturing index registed 49.3 in January, compared with 51.4 in December.

A reading below 50 indicates a contraction in U.S. manufacturing, while a reading above 50 signals growth.

The January reading was contrary to analysts' expectations of a reading of 51.5.

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