A miner by definition controls some computing power. Due to the nature of mining this computing power is commoditized ; unless you’re a miner any two rigs outputing the same hash/second are equivalent. Due to the close relation to BTC computing power is actually pretty much fungible, and often discussed in terms of shares (as from a mining pool) rather than straight hash/second.

The business of mining has some significant capital costs. The significant pressure rapid obsolescence places on mining equipment lifecycle further increases miner’s need for capital. Due to the significant risks involved many are unwilling to acquire fiat-denominated debt to finance their mining operations (even if favourable moves in the BTC-USD ratio are likely on the long term).

The perfect solution to all these problems was the invention of the PMB, or Perpetual Mining Bond. While it sounds benign enough, pretty much the only factual part of that name is the word “mining”, and this in maybe half the cases.

A PMB is an unconditional promise to pay to the holder a periodic dividend (weekly is common, daily is not unheard of) equal to the theoretical mining results a theoretical machine with given specifications would have achieved in the interval. Due to the way Bitcoin works, it is trivial to calculate this mathematically : The block reward (currently 50 BTC, likely to halve around November the 30th) times the hash output divided by the difficulty times two to the power of thirty two.

This is a perfect solution indeed, but only from the point of view of the miner, as he is now completely insulated from all risk : he takes in the investment, expends it as promised, delivers the dividends as they accrue and that’s all.

Source: trilema.com