noun
substantial increase; large gain; huge increase
Used in economic, business, or statistical contexts to describe a significant rise in numbers, amounts, or percentages.
今年の売上は前年比で大幅増となった。
This year's sales showed a substantial increase compared to the previous year.
輸出が大幅増を記録した。
Exports recorded a large gain.
増加 is a general term for 'increase', whereas 大幅増 emphasizes the magnitude of the increase.
Compound of 大幅 (おおはば, 'large, substantial') and 増 (ぞう, 'increase').