Alliance Treasure Bonus is a game mechanic that rewards alliances that have nations which possess Treasures.
Alliances by default have a 0% Alliance Treasure Bonus. When alliance members possess treasures in their nations, the entire alliance receives a bonus to their gross income. Alliance Treasure Bonus is calculated using the formula below. Alliance applicants and nations not on the same color as the alliance do not receive this bonus.
*All Formulas Are Per Turn Unless Otherwise Noted
Alliance Treasure Bonus = sqrt(Treasures In Alliance * 4)