# Soft-Pegging to the US Dollar
**How pegging works**
When the price of FXD on some market (DEX or CEX) is less than $1, the arbitrageurs are looking for an incentive to arbitrage it with the market, which has a price closer to or more than $1. The below images show how the FXD price is pegged from time 0 to time 2.
Pegging when FXD < $1
When the market price of FXD is greater than $1, it provides an incentive to sell FXD in the market. The below images show how the FXD price is pegged from time 0 to time 2.
Pegging when FXD > $1
StableSwapModule (SSM) is the special mechanism developed by the Fathom team to provide an additional incentive for arbitrageurs.
