Block subsidy

All bitcoin were issued with the launch of the network in 2009.

From this original issuance, the bitcoin are algorithmically released to miners (who act under unilateral contract) as a subsidised reward for their transaction validation services before transaction fees dominate the reward.

The block subsidy is the means by which all bitcoins available for exchange on the network are released. The mechanism is designed such that the miners who build the network infrastructure receive these rewards as a subsidy to fund their operations.

The Block Subsidy Schedule originally awarded each successful block discovery, 50 bitcoins, however the rate halves once every 210,000 blocks (approximately every 4 years). The block subsidy ceases when the halving makes the value below 1 Satoshi, an event which is estimated to take place in around 2140.

This chart shows both the rate of subsidy over time and the overall release of Bitcoins into the system. Used with permission, courtesy of Metanet.icu user 'mpapec'.