Shares of W.W. Grainger Inc. plummeted after the U.S. industrial supplier reported a year-over-year decline in third-quarter GAAP earnings, which were hit by a charge related to its Cromwell business in the U.K.

Net earnings attributable to the company came in at $104.4 million, or $1.82 per share, in the quarter that ended Sept. 30, down from $162.0 million, or $2.79 per share, a year ago.

W.W. Grainger said it recorded $139 million in noncash impairment charges in relation to Cromwell Group (Holdings) Ltd, which the company said reflected "a slower growth trajectory and structural issues."

"These issues include prolonged Brexit uncertainty that impacted the market outlook and higher discount rates, which together account for a majority of the reduction in valuation," the company said.

On an adjusted basis, W.W. Grainger earned $240.4 million in the third quarter, up from $168.5 million a year earlier. Adjusted EPS for the period was $4.19, higher than the year-ago adjusted EPS of $2.90 and the S&P Global Market Intelligence consensus normalized EPS estimate of $4.00.

The company attributed the adjusted EPS growth to higher sales, operating expense leverage and a lower tax rate.

Third-quarter net sales grew year over year to $2.83 billion from $2.64 billion, missing the S&P Global Market Intelligence consensus revenue estimate of $2.84 billion for the quarter.

Operating cash flow for the quarter was $367.1 million, up from $348.7 million a year ago.

W.W. Grainger's stock was down 12.92% shortly before 10 a.m. ET, trading at $276.915 per share.