From Longman Business Dictionary
stockpilestock·pile1 /ˈstɒkpaɪlstɑːk-/ verb [transitiveT]COMMERCE to keep adding to a large supply of goods, weapons etc that are being kept for use or possible use in the futureThe US government began stockpiling oil in response to the oil embargo.
—stockpiler noun [countableC]We have yet to see one of the big stockpilers of gold announce significant disposals.
—stockpiling noun [uncountableU]the stockpiling of chemical and biological weapons