UPDATE 3-Caterpillar beats estimates on buoyant global demand

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Jan 25 (Reuters) - Caterpillar Inc's profit trounced

forecasts for the seventh straight quarter on Thursday as buoyant global demand from construction, mining and energy industries drove a 35-percent surge in equipment sales. Its shares, however, reversed course after opening higher as investors took out profits in a stock that has risen around 80 percent in the past year. Shares in the world's largest heavy-duty equipment maker,

part of the Dow Jones industrial average , were last down

1 percent. Caterpillar took a $2.4-billion charge related to the recent U.S. tax law, widening its net loss before adjustments to $1.30 billion, or $2.18 per share, from $1.17 billion, or $2.00 per share, a year earlier. But there was little clarity about any tax-related charges in 2018, nor did the earnings report said anything about an ongoing tax investigation. Caterpillar said it saw "positive economic indicators across most of the world." It forecast stronger home and non-residential construction in North America amid growth in other regions, said mining customers are healthier and more willing to invest, and expects higher oil and gas sales this year. It also said the prices it charges customers are staying ahead of material costs. This is a dramatic turnaround for Caterpillar which, weighed down by weak economic conditions and commodity price volatility, saw a more than 40-percent fall in sales between 2012 and 2016. While the bulk of the earnings recovery in 2017 was driven economy and rebounding commodities have boosted the outlook for its other two divisions - resource industries and energy & transportation. Higher oil prices are encouraging new investments in the sector and boosting demand for equipment. Mining activity has also picked up amid rising gold, iron ore and copper prices, leading to higher demand from customers. The company forecast adjusted profit of $8.25 to $9.25 per share for 2018, above analysts' average estimate of $8.19, according to Thomson Reuters I/B/E/S. In the fourth quarter, revenue increased across all the segments, with the largest increase in North America, its biggest market. In adjusted terms, it made a profit of $2.16 per share. On that basis, analysts had expected $1.79 per share. "Expectations were elevated coming into the print, but this is a solid Q4 'beat'," analysts at J.P. Morgan wrote in a note.

(Editing by Patrick Graham and Nick Zieminski)