The Econophanic Heresy was, according to A Short Guide to Catholic Church History, a heretical belief that there was a Treasure House of Sin to counter the church's Treasure House of Grace, "drawn on by the Devil and his angels". Called an 'aberrant fantasy", the sect of Econophanes eventually became demonic and collapsed when word got around the devil gave higher interest rates (Saint Fidgeta and Other Parodies, 60).
The prefix econo- indicates it has to do with economics.
|5. A Short Guide to Catholic Church History|