In a few decades when the reward gets too small, the transaction fee will become the main compensation for nodes. I’m sure that in 20 years there will either be very large transaction volume or no volume. — Satoshi Nakamoto Since the early days of Bitcoin, we have known that one day Bitcoin would need to rely on its transaction fee market for security. For the first 210,000 blocks, Bitcoin rewarded its miners with 50 shiny new coins every 10 minutes, on top of any transaction fees they were able to include in the blocks they mined. This reward, also called a block subsidy, introduced new bitcoins into circulation and incentivized miners to commit costly hashing power to the security of the system.