When the income of an economy grows very large a part of the income is lost without being useful. Taxes lost in this way are called friction. Friction models the fact that, when a faction has large amounts of spendable tax, internal friction starts eating away at this amount. Where these taxes go depend on the culture of the faction, but it invariable disappears.

As some examples, think about increased bureaucratic councils for Socialist Republic of Niom, lavish feasts and large estates for the nobles of the Veolian Commonwealth, or extremely high bonusses for the upper echelons of all Praetorian Empire corporate boards, etc.

Friction is calculated over all spendable taxes. Spendable taxes are defined as (taxable income + trade balance - union taxation). The amount of lost due to friction is determined by the following table:

Friction Bracket	Percentage	Low Amount in Bracket	High Amount in Bracket
First 3000	0%	0	3 000
Next 3000	10%	3 001	6 000
All above this	20%	6 001	∞

This makes it so that the first 3000 spendable create no measurable friction. The next 3000 (so from 3001 to 6000 spendable income) have 10% of friction, any spendable above that will have 20% of friction.

Friction is rounded down per bracket.

The friction part of disappearing income is purely in the rules domain.