There is a controlled supply of bitcoin — only 21 million will ever be created. As more bitcoin is mined, less bitcoins are available to be unlocked within the system. In order for the system to readjust, bitcoin’s creators instituted something called “halving”, where the reward for bitcoin is decreased by 50%.

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While it was once possible to obtain a reward of 50BTC per block for mining, today, that number has decreased to 25BTC. Current projections estimate that the next halving to a 12.5BTC reward will happen in July of 2016.

Every time that a halving event occurs, it is hotly debated in the bitcoin community as to what will happen. This was the case in 2012, when the reward went down to 25BTC.

While many initially feared that the occurrence of halving in mining would cause chaos or other disruptions to the network, that hasn’t been the case. Core Developer Gregory Maxwell sees the halving simply as part of the economics of bitcoin — he believes it is a well-designed limiter of bitcoin supply over time, and that miners will simply adjust.