President-elect Donald Trump promised on Wednesday that under his presidency American infrastructure will be rebuilt, which would double U.S. economic growth. Following his victory speech, copper prices rose as much as 3.5% to $5,443 per ton. The metal closed Wednesday 3.4% higher at $5,411, marking its largest one-day rise in seven months. 

You'd have to go all the way back to July 2015 to find the last time copper prices were trading this high, driven by speculation that the president-elect could usher in more fiscal stimulus, boosting demand for copper. The resurgence in the metal sent the Global X Copper Miners ETF (COPX) rising almost 4% Wednesday to a new 52-week high. (See also: Freeport Stock Surges on Higher Copper Prices.)

Also making a new 52-week high was the world’s largest mining company BHP Billiton Limited (BHP), which grew 3.13%, while Freeport-McMoRan Inc. (FCX) surged more than 8%.

"The Republicans have control of both houses of Congress and that means there is a possibility that those kind of programs could become reality," ICBC Standard Bank analyst Tom Kendall said, according to Reuters. "Over the last few days, there has been in the market a short-term CTA-type buying momentum and investors are now looking at the next level at around $5,445."

Overall, copper has increased some 10% over the past week, driven by what investors expect to be a more industry-friendly environment. "Inventories of copper held on the LME fell for the fourteenth straight day and are now down 34% over the past six weeks," Reuters noted Wednesday.

Last month, several copper companies such as BHP and Freeport had slashed their production guidance, citing lower commodity prices. It would seem they might soon be in a position to revise their guidance upward. And investors have begun to speculate that firms such as Freeport and BHP will have no choice but to do that. (See also: BHP Lowers Iron Ore Output, Copper Guidance.)