Before everybody get unnecessarily tense, if you are not an experimented trader, borrowing and selling Bit20, there is no change for you. You still can buy and sell Bit20 as you like.

What is a black swan ?

As you all know now, Bitshares smartcoin (for ex. Bit20) are created by borrowers who lock 200% of its value in collateral (in BTS). Then, they sell those assets on the market creating the current supply.

What happens when BTS go down and the collateral shrinks?

Automatically, when the collateral goes under 175% of the value, the blockchain creates a margin call, buy back the asset in the market and cover the loan.

What happens if there is too many people trying to buy the asset and the margin call is left behind buyers?

The collateral keeps going down.

To avoid a situation in which the collateral would be lower than 100%, the blockchain has a big security. The security consists in converting all the assets in their value in BTS and block the "borrowing" function. The market remains alive, but there is no more loan allowed. This event is called a black swan and we just have experimented it on our market.

What caused it ?

We were in testing phase with only 3 witnesses sending the price feed in the DEX. It was done purposefully until we were comfortable to go professional mode with much more witnesses and different script versions producing the price feed.

The website coincap.io has provided wrong information for several markets (LTC, XMR, ZEC, STEEM et LSK) during several hours. The witnesses used, as part of their data stream, the information from there and their price feed composed by those prices has increased by around 100%. When the second of the 3 witnesses sent the wrong price feed, the median between the 3 witnesses price increase a lot, the collaterals weren't big enough and it caused the black swan.

We are at the moment in contact with the witnesses to improve the scripts so this event couldn't happen again. A security will be implemented in the code.

What are the direct consequences?

• Traders won't be able to borrow the asset during the next weeks
• As a consequence of the previous point, the total supply won't grow until the market is re-unable.

When will the market be back with all its fontionnalities?

The BSIP18 (BitShares Improvement Proposal) is currently voted in by BTS holders and will be implemented soon. We could see this market fully fonctional again in no more than 8 weeks.

Details on the BSIP18 :
BSIP18 : http://www.bitshares.foundation/workers/2017-07-peter-conrad

Details on the margin call mechanics :
http://docs.bitshares.eu/bitshares/user/dex-margin-mechanics.html

Details on the black swan :
http://bytemaster.github.io/article/2015/01/27/BitAssets-and-Black-Swan-Events/

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