What Is the Significance of a Bitcoin Halving Event on Miner Revenue?

A Bitcoin halving is a pre-programmed event that cuts the block reward for miners by 50%. Since the block reward is a major component of miner revenue, a halving immediately reduces the income generated per block by half.

Miners must rely more heavily on transaction fees and/or hope for a significant increase in the price of Bitcoin to maintain profitability. It often leads to less efficient miners shutting down.