With the reward halving just about 2 months away, I was once again thinking about the coin creation model in Bitcoin. Pros and cons.
What do you guys think it will be the best model for coin creation?
a - Something like that of bitcoin: fixed long term hard limit, with highest creation rates at the beginning (inverted exponential, or some function with a similar behaviour).
b - Constant fixed block reward rate. Effectively this make the amount unbounded but it's more than anything a psychological perception, over time coin creation would converge towards 0%.
c - Constant % growth over coin base (starting from a premined base, either usable or not, or a period of "a" or "b" - above - coin creation)
d - Something essentially different to a, b, or c. External fixing, variable depending on transactions, etc. Also, elements that could be added to a, b or c (substantial compulsory fees, demurrage, etc).
I think it's worth noting that bitcoin is not really "deflationary" and it won't be for a long time. We are still in a stage of rapid growth both in terms of users and in terms of coins. Right now, yearly monetary creation rates are still 25% yearly for this year, and after halving it will be over 10% for two more years. This is still very high for what we're used to in FIAT world in most industrialised countries in modern times. Sure, there is the perceived expectation of ~0% in the future, but this future is still decades away (under 1% first in year 17, under 0.1% first in year 29) and I don't think many people in the Bitcoin community think that long term. At some point, maybe in about 30 or 40 years, coin loss will beat coin generation.
However the bitcoin model makes general sense in relation to the expected adoption of a new technology. User adoption strongly growths early, with peaks of "viral" stages of adoption, and over time it will achieve a plateau, or even a regression given enough time. It seems reasonable that coin creation is faster at the beginning to match demand. It also allows for a relatively short time frame until we have a low coin creation rate (17 years to hit 1%, vs 100 years if coin creation was constant). So basically most of us will live to see how it is. What I think it's a bit radical is the halving policy instead of a more gradual adjustment. It definitely creates a psychological reaction that translates to the market and to the behaviour of users and miners.
bitcoin-like model, starting reward 50, 10 min per block
after year 1 100.0 % yearly growth -- block reward: 50 total monetary mass: 2629800.0
after year 2 50.0 % yearly growth -- block reward: 50 total monetary mass: 5259600.0
after year 3 33.3333333333 % yearly growth -- block reward: 50 total monetary mass: 7889400.0
after year 4 25.0 % yearly growth -- block reward: 50 total monetary mass: 10519200.0
after year 5 11.1111111111 % yearly growth -- block reward: 25.0 total monetary mass: 11834100.0
after year 6 10.0 % yearly growth -- block reward: 25.0 total monetary mass: 13149000.0
after year 7 9.09090909091 % yearly growth -- block reward: 25.0 total monetary mass: 14463900.0
after year 8 8.33333333333 % yearly growth -- block reward: 25.0 total monetary mass: 15778800.0
after year 9 4.0 % yearly growth -- block reward: 12.5 total monetary mass: 16436250.0
after year 10 3.84615384615 % yearly growth -- block reward: 12.5 total monetary mass: 17093700.0
after year 11 3.7037037037 % yearly growth -- block reward: 12.5 total monetary mass: 17751150.0
after year 12 3.57142857143 % yearly growth -- block reward: 12.5 total monetary mass: 18408600.0
after year 13 1.75438596491 % yearly growth -- block reward: 6.25 total monetary mass: 18737325.0
after year 14 1.72413793103 % yearly growth -- block reward: 6.25 total monetary mass: 19066050.0
after year 15 1.69491525424 % yearly growth -- block reward: 6.25 total monetary mass: 19394775.0
after year 16 1.66666666667 % yearly growth -- block reward: 6.25 total monetary mass: 19723500.0
after year 17 0.826446280992 % yearly growth -- block reward: 3.125 total monetary mass: 19887862.5
after year 18 0.819672131148 % yearly growth -- block reward: 3.125 total monetary mass: 20052225.0
after year 19 0.813008130081 % yearly growth -- block reward: 3.125 total monetary mass: 20216587.5
after year 20 0.806451612903 % yearly growth -- block reward: 3.125 total monetary mass: 20380950.0
after year 21 0.401606425703 % yearly growth -- block reward: 1.5625 total monetary mass: 20463131.25
after year 22 0.4 % yearly growth -- block reward: 1.5625 total monetary mass: 20545312.5
after year 23 0.398406374502 % yearly growth -- block reward: 1.5625 total monetary mass: 20627493.75
after year 24 0.396825396825 % yearly growth -- block reward: 1.5625 total monetary mass: 20709675.0
after year 25 0.19801980198 % yearly growth -- block reward: 0.78125 total monetary mass: 20750765.625
after year 26 0.197628458498 % yearly growth -- block reward: 0.78125 total monetary mass: 20791856.25
after year 27 0.197238658777 % yearly growth -- block reward: 0.78125 total monetary mass: 20832946.875
after year 28 0.196850393701 % yearly growth -- block reward: 0.78125 total monetary mass: 20874037.5
after year 29 0.0983284169125 % yearly growth -- block reward: 0.390625 total monetary mass: 20894582.8125
after year 30 0.098231827112 % yearly growth -- block reward: 0.390625 total monetary mass: 20915128.125
after year 31 0.0981354268891 % yearly growth -- block reward: 0.390625 total monetary mass: 20935673.4375
after year 32 0.0980392156863 % yearly growth -- block reward: 0.390625 total monetary mass: 20956218.75
after year 33 0.0489955903969 % yearly growth -- block reward: 0.1953125 total monetary mass: 20966491.4062
after year 34 0.048971596474 % yearly growth -- block reward: 0.1953125 total monetary mass: 20976764.0625
after year 35 0.0489476260401 % yearly growth -- block reward: 0.1953125 total monetary mass: 20987036.7188
after year 36 0.0489236790607 % yearly growth -- block reward: 0.1953125 total monetary mass: 20997309.375
after year 37 0.0244558571778 % yearly growth -- block reward: 0.09765625 total monetary mass: 21002445.7031
after year 38 0.0244498777506 % yearly growth -- block reward: 0.09765625 total monetary mass: 21007582.0312
after year 39 0.0244439012466 % yearly growth -- block reward: 0.09765625 total monetary mass: 21012718.3594
after year 40 0.0244379276637 % yearly growth -- block reward: 0.09765625 total monetary mass: 21017854.6875
after year 41 0.0122174709835 % yearly growth -- block reward: 0.048828125 total monetary mass: 21020422.8516
after year 42 0.0122159784999 % yearly growth -- block reward: 0.048828125 total monetary mass: 21022991.0156
after year 43 0.0122144863808 % yearly growth -- block reward: 0.048828125 total monetary mass: 21025559.1797
after year 44 0.0122129946263 % yearly growth -- block reward: 0.048828125 total monetary mass: 21028127.3438
after year 45 0.00610612444282 % yearly growth -- block reward: 0.0244140625 total monetary mass: 21029411.4258
after year 46 0.00610575161802 % yearly growth -- block reward: 0.0244140625 total monetary mass: 21030695.5078
after year 47 0.00610537883876 % yearly growth -- block reward: 0.0244140625 total monetary mass: 21031979.5898
after year 48 0.00610500610501 % yearly growth -- block reward: 0.0244140625 total monetary mass: 21033263.6719
after year 49 0.0030524098776 % yearly growth -- block reward: 0.01220703125 total monetary mass: 21033905.7129
after year 50 0.00305231670838 % yearly growth -- block reward: 0.01220703125 total monetary mass: 21034547.7539
fixed reward model (50 per block, 10 min per block)
after year 1 100.0 % yearly growth -- block reward: 50 total monetary mass: 2629800.0
after year 2 50.0 % yearly growth -- block reward: 50 total monetary mass: 5259600.0
after year 3 33.3333333333 % yearly growth -- block reward: 50 total monetary mass: 7889400.0
after year 4 25.0 % yearly growth -- block reward: 50 total monetary mass: 10519200.0
after year 5 20.0 % yearly growth -- block reward: 50 total monetary mass: 13149000.0
after year 6 16.6666666667 % yearly growth -- block reward: 50 total monetary mass: 15778800.0
after year 7 14.2857142857 % yearly growth -- block reward: 50 total monetary mass: 18408600.0
after year 8 12.5 % yearly growth -- block reward: 50 total monetary mass: 21038400.0
after year 9 11.1111111111 % yearly growth -- block reward: 50 total monetary mass: 23668200.0
after year 10 10.0 % yearly growth -- block reward: 50 total monetary mass: 26298000.0
after year 11 9.09090909091 % yearly growth -- block reward: 50 total monetary mass: 28927800.0
after year 12 8.33333333333 % yearly growth -- block reward: 50 total monetary mass: 31557600.0
after year 13 7.69230769231 % yearly growth -- block reward: 50 total monetary mass: 34187400.0
after year 14 7.14285714286 % yearly growth -- block reward: 50 total monetary mass: 36817200.0
after year 15 6.66666666667 % yearly growth -- block reward: 50 total monetary mass: 39447000.0
after year 16 6.25 % yearly growth -- block reward: 50 total monetary mass: 42076800.0
after year 17 5.88235294118 % yearly growth -- block reward: 50 total monetary mass: 44706600.0
after year 18 5.55555555556 % yearly growth -- block reward: 50 total monetary mass: 47336400.0
after year 19 5.26315789474 % yearly growth -- block reward: 50 total monetary mass: 49966200.0
after year 20 5.0 % yearly growth -- block reward: 50 total monetary mass: 52596000.0
after year 21 4.7619047619 % yearly growth -- block reward: 50 total monetary mass: 55225800.0
after year 22 4.54545454545 % yearly growth -- block reward: 50 total monetary mass: 57855600.0
after year 23 4.34782608696 % yearly growth -- block reward: 50 total monetary mass: 60485400.0
after year 24 4.16666666667 % yearly growth -- block reward: 50 total monetary mass: 63115200.0
after year 25 4.0 % yearly growth -- block reward: 50 total monetary mass: 65745000.0
after year 26 3.84615384615 % yearly growth -- block reward: 50 total monetary mass: 68374800.0
after year 27 3.7037037037 % yearly growth -- block reward: 50 total monetary mass: 71004600.0
after year 28 3.57142857143 % yearly growth -- block reward: 50 total monetary mass: 73634400.0
after year 29 3.44827586207 % yearly growth -- block reward: 50 total monetary mass: 76264200.0
after year 30 3.33333333333 % yearly growth -- block reward: 50 total monetary mass: 78894000.0
after year 31 3.22580645161 % yearly growth -- block reward: 50 total monetary mass: 81523800.0
after year 32 3.125 % yearly growth -- block reward: 50 total monetary mass: 84153600.0
after year 33 3.0303030303 % yearly growth -- block reward: 50 total monetary mass: 86783400.0
after year 34 2.94117647059 % yearly growth -- block reward: 50 total monetary mass: 89413200.0
after year 35 2.85714285714 % yearly growth -- block reward: 50 total monetary mass: 92043000.0
after year 36 2.77777777778 % yearly growth -- block reward: 50 total monetary mass: 94672800.0
after year 37 2.7027027027 % yearly growth -- block reward: 50 total monetary mass: 97302600.0
after year 38 2.63157894737 % yearly growth -- block reward: 50 total monetary mass: 99932400.0
after year 39 2.5641025641 % yearly growth -- block reward: 50 total monetary mass: 102562200.0
after year 40 2.5 % yearly growth -- block reward: 50 total monetary mass: 105192000.0
after year 41 2.43902439024 % yearly growth -- block reward: 50 total monetary mass: 107821800.0
after year 42 2.38095238095 % yearly growth -- block reward: 50 total monetary mass: 110451600.0
after year 43 2.32558139535 % yearly growth -- block reward: 50 total monetary mass: 113081400.0
after year 44 2.27272727273 % yearly growth -- block reward: 50 total monetary mass: 115711200.0
after year 45 2.22222222222 % yearly growth -- block reward: 50 total monetary mass: 118341000.0
after year 46 2.17391304348 % yearly growth -- block reward: 50 total monetary mass: 120970800.0
after year 47 2.12765957447 % yearly growth -- block reward: 50 total monetary mass: 123600600.0
after year 48 2.08333333333 % yearly growth -- block reward: 50 total monetary mass: 126230400.0
after year 49 2.04081632653 % yearly growth -- block reward: 50 total monetary mass: 128860200.0
after year 50 2.0 % yearly growth -- block reward: 50 total monetary mass: 131490000.0
An example for model c (after a period of a).
Initial block reward 100, 10 minutes per block, block reward decreases to 90% of itself every year, until a target yearly creation growth rate is matched (2% in this case, the discrepancy to 1.9607% comes from adjusting the block at the beginning of the year and measuring the yearly growth at year end). Target is achieved in this case in ~17 years, and then growth is fixed at ~2% a year. Initial reward adjustment is not dramatic. Coin loss is not a problem. Doubling rate at 2% is 35 years - saving is not strongly punished since 35 years is a reasonable time frame in life-time terms.
Decreasing reward converging to a given rate (2%) with a starting block reward = 100 and initial block modification rate of 0.900000 (adjusted yearly)
after year 1 100.0 % yearly growth -- block reward: 100 total monetary mass: 5259600.0
after year 2 47.3684210526 % yearly growth -- block reward: 90.0 total monetary mass: 9993240.0
after year 3 29.889298893 % yearly growth -- block reward: 81.0 total monetary mass: 14253516.0
after year 4 21.198022681 % yearly growth -- block reward: 72.9 total monetary mass: 18087764.4
after year 5 16.0215867744 % yearly growth -- block reward: 65.61 total monetary mass: 21538587.96
after year 6 12.6022549988 % yearly growth -- block reward: 59.049 total monetary mass: 24644329.164
after year 7 10.1866559735 % yearly growth -- block reward: 53.1441 total monetary mass: 27439496.2476
after year 8 8.39805729184 % yearly growth -- block reward: 47.82969 total monetary mass: 29955146.6228
after year 9 7.02712386344 % yearly growth -- block reward: 43.046721 total monetary mass: 32219231.9606
after year 10 5.94822147542 % yearly growth -- block reward: 38.7420489 total monetary mass: 34256908.7645
after year 11 5.08137313274 % yearly growth -- block reward: 34.86784401 total monetary mass: 36090817.8881
after year 12 4.37323736196 % yearly growth -- block reward: 31.381059609 total monetary mass: 37741336.0992
after year 13 3.78686585653 % yearly growth -- block reward: 28.2429536481 total monetary mass: 39226802.4893
after year 14 3.29585076819 % yearly growth -- block reward: 25.4186582833 total monetary mass: 40563722.2404
after year 15 2.88081312016 % yearly growth -- block reward: 22.876792455 total monetary mass: 41766950.0163
after year 16 2.52720808038 % yearly growth -- block reward: 20.5891132095 total monetary mass: 42849855.0147
after year 17 2.22390483982 % yearly growth -- block reward: 18.5302018885 total monetary mass: 43824469.5132
after year 18 1.96223984367 % yearly growth -- block reward: 16.6771816997 total monetary mass: 44701622.5619
after year 19 1.96078431373 % yearly growth -- block reward: 16.9981072941 total monetary mass: 45595655.0132
after year 20 1.96078431373 % yearly growth -- block reward: 17.3380694399 total monetary mass: 46507568.1134
after year 21 1.96078431373 % yearly growth -- block reward: 17.6848308287 total monetary mass: 47437719.4757
after year 22 1.96078431373 % yearly growth -- block reward: 18.0385274453 total monetary mass: 48386473.8652
after year 23 1.96078431373 % yearly growth -- block reward: 18.3992979942 total monetary mass: 49354203.3425
after year 24 1.96078431373 % yearly growth -- block reward: 18.7672839541 total monetary mass: 50341287.4094
after year 25 1.96078431373 % yearly growth -- block reward: 19.1426296332 total monetary mass: 51348113.1575
after year 26 1.96078431373 % yearly growth -- block reward: 19.5254822259 total monetary mass: 52375075.4207
after year 27 1.96078431373 % yearly growth -- block reward: 19.9159918704 total monetary mass: 53422576.9291
after year 28 1.96078431373 % yearly growth -- block reward: 20.3143117078 total monetary mass: 54491028.4677
after year 29 1.96078431373 % yearly growth -- block reward: 20.7205979419 total monetary mass: 55580849.037
after year 30 1.96078431373 % yearly growth -- block reward: 21.1350099008 total monetary mass: 56692466.0178
after year 31 1.96078431373 % yearly growth -- block reward: 21.5577100988 total monetary mass: 57826315.3381
after year 32 1.96078431373 % yearly growth -- block reward: 21.9888643008 total monetary mass: 58982841.6449
after year 33 1.96078431373 % yearly growth -- block reward: 22.4286415868 total monetary mass: 60162498.4778
after year 34 1.96078431373 % yearly growth -- block reward: 22.8772144185 total monetary mass: 61365748.4474
after year 35 1.96078431373 % yearly growth -- block reward: 23.3347587069 total monetary mass: 62593063.4163
after year 36 1.96078431373 % yearly growth -- block reward: 23.801453881 total monetary mass: 63844924.6846
after year 37 1.96078431373 % yearly growth -- block reward: 24.2774829586 total monetary mass: 65121823.1783
after year 38 1.96078431373 % yearly growth -- block reward: 24.7630326178 total monetary mass: 66424259.6419
after year 39 1.96078431373 % yearly growth -- block reward: 25.2582932702 total monetary mass: 67752744.8347
after year 40 1.96078431373 % yearly growth -- block reward: 25.7634591356 total monetary mass: 69107799.7314
after year 41 1.96078431373 % yearly growth -- block reward: 26.2787283183 total monetary mass: 70489955.7261
after year 42 1.96078431373 % yearly growth -- block reward: 26.8043028846 total monetary mass: 71899754.8406
after year 43 1.96078431373 % yearly growth -- block reward: 27.3403889423 total monetary mass: 73337749.9374
after year 44 1.96078431373 % yearly growth -- block reward: 27.8871967212 total monetary mass: 74804504.9361
after year 45 1.96078431373 % yearly growth -- block reward: 28.4449406556 total monetary mass: 76300595.0349
after year 46 1.96078431373 % yearly growth -- block reward: 29.0138394687 total monetary mass: 77826606.9356
after year 47 1.96078431373 % yearly growth -- block reward: 29.5941162581 total monetary mass: 79383139.0743
after year 48 1.96078431373 % yearly growth -- block reward: 30.1859985833 total monetary mass: 80970801.8557
after year 49 1.96078431373 % yearly growth -- block reward: 30.7897185549 total monetary mass: 82590217.8929
after year 50 1.96078431373 % yearly growth -- block reward: 31.405512926 total monetary mass: 84242022.2507
