Uphold’s staking feature works with blockchains that use the Proof Of Stake (PoS) as a consensus mechanism for validating and processing transactions and creating new blocks in a blockchain.
Virtually anyone with a minimum balance of a supported PoS token can validate transactions and earn rewards for doing so. Those rewards are credited regularly to your staking account, thereby compounding future rewards. Staking is therefore a great way to put your holdings to work for you.
Note that rewards earned for staking ETH are not re-staked, but while market conditions allow, Uphold will credit your account as if they were.