Early 18th century. From French agiotage from agioter to speculate (although this is first attested slightly later: 1716; from agio, with insertion of medial -t- by analogy with nouns ending in -ot; compare †agiot, variant of agio) + -age.
Definition of agiotage in US English:
agiotage
noun
historical
The business of money-changing.
Origin
Early 18th century. From French agiotage from agioter to speculate (although this is first attested slightly later: 1716; from agio, with insertion of medial -t- by analogy with nouns ending in -ot; compare † agiot, variant of agio) + -age.