All pies are subject to a streaming fee that is applied continuously to PieDAO products.
For AMM pies this is 0.7%. PieVaults like YPIE that have built in productivity have a 1% fee.
This fee is directed to the DAO treasury, to be used for further growth as determined by DOUGH holders.
Swap fees are earned by pie holders, providing an additional income. Because first pie smart pools are Balancer AMMs (automated market makers) they constantly rebalance to maintain the set allocation as users interact with them. This 1% fee is accrued by all holders of the pie smart pool token, with the underlyings constantly growing.