The Collaborative International Dictionary of English v.0.48:

Agiotage \Ag"i*o*tage\, n. [F. agiotage, fr. agioter to practice
   stockjobbing, fr. agio.]
   Exchange business; also, stockjobbing; the maneuvers of
   speculators to raise or lower the price of stocks or public
   funds.
   [1913 Webster]

         Vanity and agiotage are to a Parisian the oxygen and
         hydrogen of life.                        --Landor.
   [1913 Webster]

WordNet (r) 3.0 (2006):

agiotage
    n 1: a fee charged for exchanging currencies [syn: agio,
         agiotage, premium, exchange premium]