1755, from subsidy + -ize.
Originally "to pay to hire" (mercenaries, foreign troops, etc.), also of nations, "to buy neutrality or alliance." Meaning "to bribe" is from 1815. Meaning "to support by grants of (often government) money" is from 1828. Related: Subsidized; subsidizing.
[subsidize etymology, subsidize origin, 英语词源]