With bitcoin, it
is possible for a central bank or cartel of central banks to control the bitcoin money supply. The important thing to understand is that stored bitcoins are indistinguishable from lost bitcoins. Bitcoins only really have value when they are spent. This means that the Central Banks can buy bitcoin when they want to raise the price, and sell bitcoin when they want to lower the price. Through this process, they are able to control the
rate of deflation up until they run out of coins to sell (run-away deflation).
Decentralized Central Banking ProposalThe OP was interested in a floor price. It is possible for a group of people to cooperate and share the risk of setting a "soft" floor price. Buy strategy shamelessly stolen from a post I saw months ago. Let's say each participant agrees to invest $10 USD for each "soft" floor. Using your favorite exchange, the buy orders would look something like this:
- Buy 100 BTC at $0.1 USD/BTC
- Buy 200 BTC at $0.05 USD/BTC
- Buy 400 BTC at $0.025 USD/BTC
- Buy 800 BTC at $0.0125 USD/BTC
- Buy 1600 BTC at $0.0625 USD/BTC
- Buy 3200 BTC at $0.03125 USD/BTC
The above buy walls each cost $10 USD for a total of $60 USD. Two people cooperating in this manner don't even need to agree on a specific floor price to share the risk. For example, somebody can invest $10 in a Buy for 142.86 BTC at $0.07 USD/BTC. The above buy walls would absorb a sell of up to 242.86 BTC while keeping the price above $0.05.
Where it gets interesting is when you start trying to use these unwanted bitcoins to try to control the rate of deflation. Anybody with a significant amount of bitcoins can use the same strategy to set a sell wall going in the opposite direction. For the purposes of discussion, let's say we want to limit the rate of deflation to 1000%/year (during the initial growth period). Without checking, I am going to pretend I found the weighted average price from a year ago was $0.30 USD/BTC. 11 times that corresponds to $3.3 USD/BTC (which until recently was below the average price). If you wanted to sell up to 127BTC, you could set up the following sell walls:
- Sell 1 BTC at $3.3 USD/BTC
- Sell 2 BTC at $6.6 USD/BTC
- Sell 4 BTC at $13.2 USD/BTC
- Sell 8 BTC at $26.4 USD/BTC
- Sell 16 BTC at $56.8 USD/BTC
- Sell 32 BTC at $105.6 USD/BTC
- Sell 64 BTC at $211.2 USD/BTC
The sell walls should probably be re-evaluated/replenished daily. As before, several individuals can share the risk of setting a ceiling, even if they disagree what exactly the ceiling should be. For example, somebody who thinks deflation should be 10,000%/year may set their ceiling to $30.3 USD/BTC.
Edit: Central banks actually use Interest rates control economic growth.