Merge branch 'master' into bsip35
abitmore
commit
a52ca3919f
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@ -37,3 +37,8 @@ Number | Title |
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[27](bsip-0027.md) | Asset Issuer Reclaim Fee Pool Funds | Abit More | Protocol | Accepted
|
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[28](bsip-0028.md) | Worker Proposal Improvements | Bill Butler | Protocol | Draft
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[29](bsip-0029.md) | Asset issue change to require owner authority | Fabian Schuh | Protocol | Draft
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[30](bsip-0030.md) | Always Allow Increasing Collateral Ratio If Debt Not Increased | Abit More | Protocol | Draft
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[31](bsip-0031.md) | Update Short Position's Margin Call Price After Partially Called Or Settled | Abit More | Protocol | Draft
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||||
[32](bsip-0032.md) | Always Match Orders At Maker Price | Abit More | Protocol | Draft
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[33](bsip-0033.md) | Maker Orders With Better Prices Take Precedence | Abit More | Protocol | Draft
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||||
[34](bsip-0034.md) | Always Trigger Margin Call When Call Price Above Or At Price Feed | Abit More | Protocol | Draft
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@ -0,0 +1,71 @@
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BSIP: 0030
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Title: Always Allow Increasing Collateral Ratio If Debt Not Increased
|
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Author: Abit More <https://github.com/abitmore>
|
||||
Status: Draft
|
||||
Type: Protocol
|
||||
Created: 2018-02-16
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Discussion: https://github.com/bitshares/bitshares-core/issues/583,
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||||
https://github.com/bitshares/bitshares-core/issues/672
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||||
Replaces: -
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||||
Worker: To be done
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# Abstract
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Currently, when a short position's collateral ratio is below MCR (a parameter
|
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in price feed: `maintenance_collateral_ratio`) but is not completely filled
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immediately due to a lack of enough volume on the opposite side of the market,
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it will hang in the market and be waiting for being margin called.
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The owner then can adjust the order's collateral ratio **only if**
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* to close the position, or
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* the new collateral ratio is above MCR, or
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* the call order get completely filled (margin called) immediately.
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While this prevents shorters from maliciously reducing collateral ratio (to
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increase possibility of black swan event), it also prevents shorters from
|
||||
slightly increasing collateral ratio (to decrease possibility of black swan
|
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event).
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This BSIP proposes a mechanism to improve this situation.
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# Motivation
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Make the exchange system more user-friendly.
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# Rationale
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The ecosystem would get benefit if shorters are allowed to reduce risks to
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themselves while reducing risks to the system at same time.
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Current rules are a bit too strict, which can be loosed to:
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A shorter can adjust the position's collateral ratio **only if**
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* to close the position, or
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* the new collateral ratio is above MCR, or
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* the call order get completely filled (margin called) immediately, or
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* **the new ratio is higher than old ratio and debt is not increased**
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# Specifications
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In `do_apply()` function of `call_order_update_evaluator` class, if
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finally found the call order still in margin call territory,
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* don't throw an exception if `call_obj->collateralization()` is reduced, and
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* require `delta_debt` of `call_order_update_operation` to be non-positive.
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# Discussion
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[to be added if any]
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# Summary for Shareholders
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||||
[to be added if any]
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||||
|
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# Copyright
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||||
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This document is placed in the public domain.
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||||
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# See Also
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||||
|
||||
* https://github.com/bitshares/bitshares-core/issues/583
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||||
* https://github.com/bitshares/bitshares-core/issues/672
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* https://bitsharestalk.org/index.php?topic=25926.0
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@ -0,0 +1,65 @@
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BSIP: 0031
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Title: Update Short Position's Margin Call Price After Partially Called Or Settled
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Author: Abit More <https://github.com/abitmore>
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Status: Draft
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Type: Protocol
|
||||
Created: 2018-02-16
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Discussion: https://github.com/bitshares/bitshares-core/issues/343,
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https://github.com/bitshares/bitshares-core/issues/649
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||||
Replaces: -
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||||
Worker: To be done
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# Abstract
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Currently, when a short position get partially called or settled, the call
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price won't change, that said, even if its actual collateral ratio is higher
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than others, higher than minimum required, it will still be selling collateral
|
||||
at a low price, taking precedence over other short positions.
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|
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This behavior is causing several issues:
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||||
* it's somehow unfair, thus brought bad experience to shorters, and
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* it prevents black swan event from being triggered in time when needed,
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because the collateral ratio of the 2nd even overall short positions may
|
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be too low but not being checked, thus risks the pegging system.
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||||
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||||
This BSIP proposes a mechanism to improve this situation.
|
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|
||||
# Motivation
|
||||
|
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Make the exchange system more user-friendly.
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||||
|
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# Rationale
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To attract more users, the system should be fair, should be well balanced.
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It's common sense that short positions with least collateral ratio should
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get margin called first. This can be achieved if always update the margin
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call price after every fill.
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# Specifications
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||||
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In `fill_order( const call_order_object& ...)` function of `database` class,
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update `call_price` field of `call_order_object` after debt or collateral
|
||||
changed to a non-zero value.
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||||
In addtion, after `call_price` get updated, the iterators initialized with
|
||||
`by_price` index may be invalidated, so need to review / revise involved code,
|
||||
E.G. `check_call_orders(...)` function of `database` class.
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||||
|
||||
# Discussion
|
||||
|
||||
[to be added if any]
|
||||
|
||||
# Summary for Shareholders
|
||||
|
||||
[to be added if any]
|
||||
|
||||
# Copyright
|
||||
|
||||
This document is placed in the public domain.
|
||||
|
||||
# See Also
|
||||
|
||||
* https://github.com/bitshares/bitshares-core/issues/343
|
||||
* https://github.com/bitshares/bitshares-core/issues/649
|
||||
* https://bitsharestalk.org/index.php?topic=25926.0
|
||||
|
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@ -0,0 +1,104 @@
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|||
BSIP: 0032
|
||||
Title: Always Match Orders At Maker Price
|
||||
Author: Abit More <https://github.com/abitmore>
|
||||
Status: Draft
|
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Type: Protocol
|
||||
Created: 2018-02-16
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Discussion: https://github.com/bitshares/bitshares-core/issues/338
|
||||
Replaces: -
|
||||
Worker: To be done
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|
||||
# Abstract
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Currently, under most circumstances, when matching two orders, the maker price
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will be used to calculate how much each order will pay and receive.
|
||||
However, when matching a taker limit order with a maker margin call order,
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the taker price is being used.
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||||
This BSIP proposes a principle: always match orders at maker price.
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||||
# Motivation
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||||
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||||
Generally, the order that is placed earlier (the maker) sets a price,
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another order that is placed later (the taker) accepts the price, thus a match,
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||||
two orders pay to each other at that price.
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||||
|
||||
Take the pure limit order matching mechanism in BitShares as an example:
|
||||
If one person (A) placed a limit
|
||||
order to sell 100 BTS at 0.1 USD per BTS, another person (B) then placed a new
|
||||
limit order to buy 100 BTS at 0.105 USD per BTS, the two orders will match at
|
||||
0.1 USD per BTS, so A will pay 100 BTS and get 10 USD, B will pay 10 USD and
|
||||
get 100 BTS.
|
||||
|
||||
However, in BitShares, when matching a taker limit order with a maker margin
|
||||
call order, the taker price is being used.
|
||||
For example, if trader A's margin call order is
|
||||
selling 100 BTS at no less than 0.1 USD per BTS, then trader B placed an order
|
||||
that buys 100 BTS at 0.105 USD per BTS, the two order will match at 0.105 USD
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||||
per BTS, so A will pay 100 BTS and get 10.5 USD, B will pay 10.5 USD and get
|
||||
100 BTS.
|
||||
|
||||
While not strictly a bug, this behavior is unexpected and irritating for users.
|
||||
|
||||
# Rationale
|
||||
|
||||
Matching orders at the maker price, with margin calls being inlined in the
|
||||
order book, is an easy to understand rule and matches user expectations,
|
||||
see [bitshares-core
|
||||
issue #338](https://github.com/bitshares/bitshares-core/issues/338).
|
||||
|
||||
There is a parameter in price feed named MSSR, which stands for "maximum short
|
||||
squeeze ratio". Maker price of margin call orders is MSSP, which stands for
|
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"maximum short squeeze price", is calculated as `feed_price / MSSR`.
|
||||
Note: `feed_price` here is in terms of debt/collateral, aka "how much debt per
|
||||
collateral".
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||||
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||||
Currently a black swan event will occur when the call order with least
|
||||
collateral ratio is going to be matched below 100% collateral ratio price
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(name it `100CRP`). Because the call order will be matched with incoming limit
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order at limit order's price (taker price),
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which can be higher or lower than 100CRP, so even if MSSP is below 100CRP,
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||||
an incoming taker limit order may or may not trigger a black swan.
|
||||
So it makes sense to check if a black swan event will occur every time when a
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limit order is created.
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||||
After the behavior changed to always match at maker price, when MSSP is below
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100CRP, an incoming taker limit order will always trigger a black swan event.
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So it makes sense to trigger the black swan event when MSSP is below 100CRP
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rather than waiting for an incoming limit order. That means it's no longer
|
||||
needed to check for black swan event when a limit order is created.
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Since checking for black swan event is somehow expensive, we'll gain a side
|
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benefit on performance with the change.
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||||
# Specifications
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||||
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||||
Matching between a limit order and a call order is done in
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`check_call_orders(...)` function of `database` class, price of limit order
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||||
is always used. It need to be changed to use MSSP when the call order is maker.
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||||
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||||
When triggering a black swan event when MSSP is below 100CRP,
|
||||
sometimes the short
|
||||
position with least collateral ratio may still have more than 100% collateral
|
||||
ratio. In this case, the global settlement price is 100CRP but not the actual
|
||||
collateral ratio of the short position with least collateral ratio.
|
||||
This is current behavior, it's fair, no need to change.
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||||
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||||
# Discussion
|
||||
|
||||
It might seem unfair on the shorter to match at MSSP even if the incoming order
|
||||
specifies a better price. However, in a rationally acting market users will not,
|
||||
in the presence of margin calls, create limit orders below the MSSP.
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||||
Effectively the new rule doesn't change this situation.
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||||
|
||||
# Summary for Shareholders
|
||||
|
||||
[to be added if any]
|
||||
|
||||
# Copyright
|
||||
|
||||
This document is placed in the public domain.
|
||||
|
||||
# See Also
|
||||
|
||||
* https://github.com/bitshares/bitshares-core/issues/338
|
||||
* https://bitsharestalk.org/index.php?topic=25926.0
|
||||
|
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@ -0,0 +1,136 @@
|
|||
BSIP: 0033
|
||||
Title: Maker Orders With Better Prices Take Precedence
|
||||
Author: Abit More <https://github.com/abitmore>
|
||||
Status: Draft
|
||||
Type: Protocol
|
||||
Created: 2018-02-17
|
||||
Discussion: https://github.com/bitshares/bitshares-core/issues/625,
|
||||
https://github.com/bitshares/bitshares-core/issues/453
|
||||
Replaces: -
|
||||
Worker: To be done
|
||||
|
||||
# Abstract
|
||||
|
||||
Currently, in BitShares, under certian circumstances, a taker order may be
|
||||
matched with a maker order which is not "on the top" of the order book.
|
||||
This behavior is unexpected and irritating for users.
|
||||
|
||||
This BSIP proposes a principle: always match taker orders with maker orders
|
||||
with the best prices (aka on the top of the order book) first.
|
||||
|
||||
# Motivation
|
||||
|
||||
As expected, when matching taker limit orders with maker limit orders, the maker
|
||||
limit orders with better prices will always be matched first.
|
||||
|
||||
For example, if trader A has a limit order selling 100 BTS at
|
||||
0.1 USD per BTS, trader B has a limit order selling 100 BTS at 0.09 USD per BTS,
|
||||
which means B's limit order has a better price for the opposite side to buy.
|
||||
Now if trader C placed an order that buys 10 BTS at 0.105 USD per BTS, B's
|
||||
limit order will take precedence, A's limit order won't be matched.
|
||||
|
||||
However, when there are (maker) margin call orders in the market which have met
|
||||
the requirements that to be matched (able to be margin called), they always
|
||||
take precedence over the (maker) limit orders on the same side, no matter
|
||||
whether the limit orders provided better price.
|
||||
|
||||
For example, if trader A's margin call order is selling 100 BTS at no less than
|
||||
0.1 USD per BTS, trader B has a limit order selling 100 BTS at 0.09 USD per BTS,
|
||||
which means B's limit order has a better price for the opposite side to buy.
|
||||
Now if trader C placed an order that buys 10 BTS at 0.105 USD per BTS, A's
|
||||
margin call order will take precedence, B's limit order won't be matched. That
|
||||
means C is forced to "buy high" when have chance to "buy low", which is
|
||||
unexpected.
|
||||
|
||||
Users have been confused by this behavior, as discussed in [bitshares-core
|
||||
issue #625](https://github.com/bitshares/bitshares-core/issues/625) and other
|
||||
threads.
|
||||
|
||||
Another scenario is described in [Bitshares-core
|
||||
issue #453](https://github.com/bitshares/bitshares-core/issues/453)
|
||||
that sometimes a taker margin call order may be matched with a maker limit order
|
||||
which is not on the top of the order book. This can be seen as a bug.
|
||||
|
||||
# Rationale
|
||||
|
||||
Always matching taker order (e.g. a buy) with a maker order which offered best
|
||||
price (aka lowest ask), is a simpler rule which most users would understand
|
||||
easily.
|
||||
|
||||
There is a parameter in price feed named MSSR, which stands for "maximum short
|
||||
squeeze ratio". Maker price of margin call orders is MSSP, which stands for
|
||||
"maximum short squeeze price", is calculated as `feed_price / MSSR`.
|
||||
Note: `feed_price` here is in terms of debt/collateral, aka "how much debt per
|
||||
collateral".
|
||||
|
||||
That said, the price that margin call orders are offering is MSSP. The prices
|
||||
those limit orders are offering are the limit prices.
|
||||
|
||||
When placing a limit (e.g. buy) order with a price beyond the lowest sell,
|
||||
the order is expected to "walk the book", matching each order on the opposite
|
||||
side in turn, at that order's price, until the new limit order is completely
|
||||
filled, or there is no more sell order matching its price.
|
||||
|
||||
To meet the expectation,
|
||||
* firstly, we need to match the limit buy order with the limit sell orders
|
||||
whose prices are lower than MSSP and prices can match the new order;
|
||||
* then, if the new limit buy order hasn't been completely filled, match it with
|
||||
the margin calls if MSSP can match the new order's price;
|
||||
* then, if the new limit buy order still hasn't been completely filled, match it
|
||||
with the rest sell orders until it's completely filled or no more sell order
|
||||
matching its price
|
||||
|
||||
|
||||
# Specifications
|
||||
|
||||
## Matching a taker limit order
|
||||
|
||||
New limit order is being processed in `apply_order(...)` function of `database`
|
||||
class.
|
||||
|
||||
Currently, in the function, firstly call orders will be checked and matched.
|
||||
After that, limit orders on the opposite side will be checked and matched.
|
||||
|
||||
Need to change the logic to:
|
||||
1. firstly, sort the limit orders on the opposite by `price`, best price first,
|
||||
end at MSSP; check them one by one, calls `match(...)` function until the
|
||||
return value is not `2` which means the new order is completely filled;
|
||||
2. if reach the end (MSSP), which means the new order is still unfilled,
|
||||
call `check_call_orders(..)` function or an equivalent;
|
||||
3. check if `new_order_object` still exist, if yes, redo step one but set the
|
||||
maximum possible price of the market as end price.
|
||||
|
||||
## Matching taker margin call orders
|
||||
|
||||
For [bitshares-core
|
||||
issue #453](https://github.com/bitshares/bitshares-core/issues/453),
|
||||
in `check_call_orders(...)` function of `database` class,
|
||||
iterator `limit_itr` will move forward when variable `filled_limit` is `true`.
|
||||
`filled_limit` will be set to `true` when a limit order get completely filled.
|
||||
However, since `filled_limit` is declared out of the `while` block,
|
||||
it doesn't get reset to `false` after `limit_itr` moved forward. That means
|
||||
after the first limit order get completedly filled, `filled_limit` will always
|
||||
be `true`, so `limit_itr` will always move forward no matter whether *current*
|
||||
limit order got completedly filled, so a taker call order may match
|
||||
with a limit order that is not on the top of the order book.
|
||||
|
||||
To fix this, need to change the code to make sure `limit_itr` always references
|
||||
the limit order on the top of the order book when dereferencing.
|
||||
|
||||
# Discussion
|
||||
|
||||
[to be added if any]
|
||||
|
||||
# Summary for Shareholders
|
||||
|
||||
[to be added if any]
|
||||
|
||||
# Copyright
|
||||
|
||||
This document is placed in the public domain.
|
||||
|
||||
# See Also
|
||||
|
||||
* https://github.com/bitshares/bitshares-core/issues/625
|
||||
* https://github.com/bitshares/bitshares-core/issues/453
|
||||
* https://bitsharestalk.org/index.php?topic=25926.0
|
||||
|
|
@ -0,0 +1,104 @@
|
|||
BSIP: 0034
|
||||
Title: Always Trigger Margin Call When Call Price Above Or At Price Feed
|
||||
Author: Abit More <https://github.com/abitmore>
|
||||
Status: Draft
|
||||
Type: Protocol
|
||||
Created: 2018-02-18
|
||||
Discussion: https://github.com/bitshares/bitshares-core/issues/606
|
||||
Replaces: -
|
||||
Worker: To be done
|
||||
|
||||
# Abstract
|
||||
|
||||
Currently, in BitShares, a short position may be margin called only when both
|
||||
two requirements are met:
|
||||
* call price is above or equal to median price feed
|
||||
* no limit order on the book is buying collateral with price higher than the
|
||||
short position's call price
|
||||
|
||||
This behavior has led to certain confusion and anger among market participants.
|
||||
|
||||
This BSIP proposes a new behavior to improve the situation: drop the second
|
||||
requirement, trigger margin call when the first requirement is met.
|
||||
|
||||
# Motivation
|
||||
|
||||
To avoid ambiguity, in this article, all prices are in terms of
|
||||
`debt asset / collateral asset`, aka how much debt asset per collateral
|
||||
asset. A bid is an order to buy collateral asset with debt asset.
|
||||
|
||||
Generally, a short position may be margin called when its collateral ratio is
|
||||
below or equal to maintenance collateral ratio (MCR).
|
||||
|
||||
However, to calculate collateral ratio, a fair collateral price is needed.
|
||||
|
||||
In BitShares, there are two data sources can be used to decide the fair
|
||||
collateral price:
|
||||
* the internal market
|
||||
* the price feeds
|
||||
|
||||
Currently, both data sources are used. Specifically, collateral price is decided
|
||||
as the higher one between the highest bid price on the internal market and the
|
||||
median price feed. That said, when a short position's collateral ratio has
|
||||
fallen to below or equal to MCR according to median price feed (in this case,
|
||||
call price of the short position is above or equal to median price feed), if
|
||||
there is a bid on the market with high price, the short position won't be margin
|
||||
called.
|
||||
|
||||
This mechanism has led to certain confusion and anger among market participants.
|
||||
* there are often orders with overlapping price on the book but didn't fill
|
||||
* there are often short positions selling collaterals with low prices, but
|
||||
traders are unable to buy at those prices
|
||||
* it often causes borrowers to sell collaterals at a low price when have chances
|
||||
to sell at higher price
|
||||
* market manipulators / arbitrage traders have more chances to force borrowers
|
||||
to sell collaterals at lower price
|
||||
|
||||
This BSIP effectively proposes a new behavior: derive the fair collateral price
|
||||
only from price feeds.
|
||||
|
||||
# Rationale
|
||||
|
||||
Since price feeds are provided by a set of chosen producers, the median price
|
||||
feed is usually considered trustworthy. On the other hand, instant market
|
||||
price is not as reliable, especially for the markets with poor depth, so it's
|
||||
a rather limited supplement for calculating collateral price.
|
||||
|
||||
At this moment, changing the rule to only use median price feed will clear away
|
||||
the confusion the end users may have, while still keeping the derived collateral
|
||||
price fair to an extent.
|
||||
|
||||
After this change is done, placing a new limit order will no longer trigger a
|
||||
margin call, cancelling a limit order or expiring a limit order will no longer
|
||||
trigger a margin call as well, that means we don't need to check for new margin
|
||||
calls nor black swan events in those scenarios, so we'll gain a side benefit on
|
||||
performance.
|
||||
|
||||
# Specifications
|
||||
|
||||
In `check_call_orders(...)` function of `database` class, when matching a call
|
||||
order with a limit order, there is a check:
|
||||
`if( match_price > ~call_itr->call_price )`, when the result is `true`,
|
||||
processing will be ended and `margin_called` will be returned.
|
||||
Need to skip the check and the following `return` action.
|
||||
|
||||
In `do_apply(...)` function of `limit_order_cancel_evaluator` class, and
|
||||
similar code blocks after a limit order object is removed, no longer need to
|
||||
call `check_call_orders(...)` function of `database` class.
|
||||
|
||||
# Discussion
|
||||
|
||||
[to be added if any]
|
||||
|
||||
# Summary for Shareholders
|
||||
|
||||
[to be added if any]
|
||||
|
||||
# Copyright
|
||||
|
||||
This document is placed in the public domain.
|
||||
|
||||
# See Also
|
||||
|
||||
* https://github.com/bitshares/bitshares-core/issues/606
|
||||
* https://bitsharestalk.org/index.php?topic=25926.0
|
||||
Loading…
Reference in New Issue