In return for providing liquidity ("staking"), users earn a share of the exchange fees generated.
This service is fully custodial.
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For more detailed information:
https://bitcoinvn.io/news/how-does-staking-on-bitcoinvn-work/
https://bitcoinvn.io/news/bitcoinvn-staking-service-hacked/
https://bitcoinvn.io/news/bitcoinvn-staking-program-frequently-asked-questions/