ShapeShift uses a flat-rate miner fee for every transaction we facilitate, regardless of the size of the transaction. This relatively high miner fee ensures that our users are able to receive their funds as quickly as possible without experiencing delays due to network congestion.
In the event that your deposit is returned to you, you will notice that a miner fee is deducted from your original deposit amount. This is the miner fee required for us to send your crypto back to you in a timely manner.
This can disproportionately impact smaller value transactions.
You can see our miner fees here.