Bitcoin miners' reserves have plunged to a 12-year low as the eagerly awaited halving event approaches, potentially slashing their earnings in half.

According to IntoTheBlock, bitcoin reserves held by miners have significantly dropped, standing at their lowest level in over a decade. Currently, leading mining pools such as Viabtc, Bitfury, and Antpool hold approximately 1.92 million BTC. This period has also seen a steady decline in reserves and a 52% increase in miner outflows.

The global Bitcoin network hashrate is currently lower than its previous high of 714.89 EH/s, recorded on March 24, and now stands at 624 EH/s. This decline is expected to have a significant impact, especially on mining operations with lower efficiency, as the block reward reduction will further exacerbate existing problems.

The scheduled halving will cut rewards in half, resulting in a weekly reduction of $445 million in miners' earnings. This change will significantly impact miners' profit from block rewards, with experts predicting a loss of approximately $10 billion. Historically, periods after halving have seen price surges that help restore miners' earnings. However, this particular bull run may produce different results due to the absence of a pre-halving rise, possibly caused by Bitcoin ETF launches.

Transaction fees, which once accounted for a significant portion of miners' revenue, now contribute only a small fraction. This week, transaction fees contributed only $11 million, while block rewards made up the bulk of earnings. The proportion of on-chain miner rewards has fallen to an all-time low of 0.08% and is expected to decrease further after the halving.

The approval of spot Bitcoin ETFs has led to a surge in market sales, forcing miners to reduce their reserves and increase prices. Miners holding approximately $1 billion have reportedly transferred their holdings to exchanges following the ETF approvals, indicating a strategic plan to mitigate the potential effects on their liquidity post-halving.

Furthermore, a decrease in Bitcoin inflows to centralized exchanges from miners has been observed, with last month's inflows falling to 374 BTC from 1,388 BTC the previous month. This reduction suggests a cautious approach by miners, aiming to hold onto their assets in anticipation of future price increases.