2020-11-15 Old bitCNY parameters adjustment

[abit]

Purpose:
to restore the peg of bitCNY in the long run and mitigate the issue that some debt positions' collateral ratio is too low.

Changes:
MCR (Maintenance collateral ratio) adjusted from 275% to 290%
The maximum supply is adjusted from 21,000,000 bitCNY to 20,000,000 bitCNY.

Current parameters:

ICR (Initial collateral ratio) 330%
MCR (Maintenance collateral ratio) 290%
MSSR (Maximum short-squeeze ratio) 190%
MCFR (Margin call fee rate) 7%
FSO (Force settlement price offset) 2%
FSFP (Force settlement fee percent) 1%

The median feed price is 0.22 CNY/BTS.

Borrowing is enabled. The maximum supply is limited to 20,000,000 bitCNY.


Note:

* As of writing, market trading price of BTS on CEXs is around 0.12 CNY, the collateral ratio (CR) of the debt position with the lowest CR in the BitShares DEX is 150%, the corresponding black swan price is 0.08 CNY.

* the ICR value 330% for feed price 0.22 effectively means 180% for market price 0.12, and the corresponding black swan price is 0.0667:
0.22 / 330% = 0.120 / 180% = 0.0667

* the MCR value 290% for feed price 0.22 effectively means 158.2% for market price 0.12, and the corresponding black swan price is 0.076:
0.22 / 290% = 0.12 / 158.2% = 0.076

* the MSSR value 190% for feed price 0.22 means collateral of low-CR debt positions will be listed for sale at 0.22 / 190% = 0.1158 bitCNY
** the MCFR value 7% means the price for buyers' is 0.22 / (190%-7%) = 0.120218579 bitCNY
** 0.1158 / 0.12 = 96.5% which means the actual penalty for being margin called is 3.5%