Bitcoin Forum

Even though I represent Bitcoinica on daily basis, I do not take any responsibility if this post in anyway affects your trading outcome.


This post serves as a guide to help you determine which price will trigger forced liquidation. This post assumes your maintenance margin requirement is 4% or 25:1, which is applicable for typical Bitcoinica users.

Some Background

Actual leverage = trade value / net value

net value = margin balance + unrealized P/L
trade value = base price * amount

The actual leverage of your account is dynamic. When you make a profit, the leverage is lower, and when you make a loss, the leverage is higher. However, you must meet the minimum requirement of margin, which determines that the highest leverage tolerated is 25:1 when you make a loss.

This means, at any time, your net value must be at least 4% of your trade value.

The FULL formula

If you are LONG,

"Zhoutonging price" = current bid - (margin balance + unrealized P/L - (base price * amount * 4%)) / amount

If you are SHORT,

"Zhoutonging price" = current ask + (margin balance + unrealized P/L - (base price * amount * 4%)) / amount

The SIMPLIFIED formula

You can get some figures from Bitcoinica UI directly. Then,

"Zhoutonging price" = current ask + (net value - maintenance) / amount

OR

"Zhoutonging price" = current bid - (net value - maintenance) / amount

EDIT:

This is important. If you have BTC balance, you must add that into your long position amount, or subtract it from your short position amount. At any point, your "zhoutonging price" should be constant regardless of market price if you don't trade.

Am I to understand this as current ask DIVIDED BY bid, or current ask OR bid?

That was unclear. Edited. Thanks!

Is it possible to get a different margin requirement?

Thanks Zhou, at last it is clear to me. I've been trading on margin for about 5 years and I am used to calculating leverage, expected profit, stops and margin calls in my head, just by looking at the prices of what I'm trading.

Until this post, I could not for the life of me figure out what your calculations were. I still don't get the logic behind it, but at least it is clear.

Alright let's plug in some numbers and see if I have this correct:

5.5 * 90 * 0.04 = 19.8
margin + unrealized P/L = 174
174-19.8 = 154.2
154.2 / 90 = 1.7133333333333333
And so the price at which this position would be Zhoutonged would be current bid - 1.71 ?

Yes I believe now I will be able to use Bitcoinica much more efficiently.

From the user's perspective:
Mistake 1) will assume he has a typical "maintenance margin requirement" with no idea how close to typical it actually is
Mistake 2) will assume a constant margin balance, when actually that margin balance will decrease as the price of bitcoin decreases
Mistake 3) will calculate the "zhoutonging price" based on the current bid, which will of course change.  Checks back later when the bid is lower, and suddenly their "zhoutonging price" is different than what they calculated using "current bid".  Maybe even zhoutonged already.

Three strikes and you're out.

How about a formula for the "zhoutonging price" which uses variables instead of constants?

Yes, it is. But only for very special accounts.

Normally we don't accept such requests.

I think it is important to tell people if they only have BTC in their currency account, then some strange effects happen.

---
First going long:
Namely, that even if you are trading with a 1:1 leverage you will get force liquidated at around 50% loss (assuming you are all in), not at 96% as in the account settings.

This is because when the BTC price drops then in addition to your P/L dropping your margin balance is also dropping. They basically meet at the halfway point.

On the good side, when the BTC price rises your margin balance increases. This means you are always able to buy relative to your BTC level in your currency account. That way you can always buy the same number of BTC no matter how high the price is. Your profits will be double, once in the P/L at Bitcionica and once in the value of your BTC in the currency account.

So with only BTC in your currency account you already effectively have a 2:1 leverage (even at 1:1 account setting)!

So, correct me if I'm wrong on this, but this means in this case (100% BTC in account) you must effectively calculate an increased leverage of your account settings (double?).

---
Second going short:
Here it also strange. If you go short with 100% BTC in your currency account then you make a profit but likewise your margin balance also goes down. So effectively you are gaining nothing (because your drop in value of your currency account offsets your profit). It's as if you have sold at the original price. If the price goes up you make a loss but also a gain in the value of your currency account, so again effectively no gain. This is at 1:1 leverage. For higher leverages I think you must halve the leverage (I think).



Is this correct Zhoutong?

1) You're typical unless you explicitly request for a change (which will be rejected most likely).

2) Just a simple tweak will adjust for BTC balance. Original post edited.

3) If current price has changed, the net value should change too. The result should be consistent.

Thanks, I'm somewhat relieved now.  Hopefully bitcoinica users will be better on their guard. 

A massive influx of new people is already starting.  Most will not be experienced in trading of any sort let alone margin trading.  We know you realize that when your customers are losing, its bad for your business.  So its surprising that the zhoutong price isn't calculated and visible on the user's account stats. 

Any chance you'll add this value as a field on bitcoinica, so users don't have to calculate it manually?

I just want to bump this to make sure I understand correctly.

Zhoutong, I think this is quite important. Though your site is pretty clear for people who understand what they're doing I think you should make your site more newcomer-friendly than it is now. Starting with bitcoinbull's suggestion.

Please explain how "Tolerated loss" is calculated / used

http://i41.tinypic.com/11wdq1i.png

It's not the same as "Maintenance margin".

Thanks for the info, bitcoinica has been great so far !

I made a simple script for adding this price to the Bitcoinica UI. Looks like this:

http://dl.dropbox.com/u/1127246/Screenshots/y~-i.png

Download it here: http://dl.dropbox.com/u/1127246/bitcoinica.user.js (http://dl.dropbox.com/u/1127246/bitcoinica.user.js)

Drag it onto your Chrome browser window (should work in any browser that supports Greasemonkey scripts but I didn't test it elsewhere) and you're done. Hope it helps someone!

Note: this is my first real take on UserScripts. Any suggestions are welcome. Also, Bitcoinica UI refreshes in unusual way (instead of updating specific elements they pull whole tables with AJAX). That's why UI could flicker a bit with this (even though I'm intercepting the updater function with my code really early), I can't help with that.

Edit: Second note: this doesn't take account for LIMIT / STOP orders that you have between the current price and the min price. Maybe it will, someday.

Works great in chrome, thanks! Does not seem to be working in Firefox 10 though.

I really appreciate that. Please PM me your Bitcoin address or Bitcoinica username to get a 3.14159265 BTC bounty!

Off-topic: I received Google Alerts about this, and when I saw "pastebin", I thought it was a database dump, LOL...

Work great here too, thank you. Could you make it also work with session login with www.bitcoinica.com? Thanks.

Thanks. I've updated the script to work with www.bitcoinica.com. Please re-download it.

Hehe, this made me chuckle, I would have loved to have seen your face (I empathise for I am in a similar position with my work)

;)

Thanks, good job.

Thanks! This is really useful.

I think it would be productive if you included a calculator somewhere on your site to calculate the maximum number of units that can be traded without getting a margin call.



Is the "amount" here the number of Bitcoins bought/sold?

Do you mean instead

"Zhoutonging price" = current ask + [ (net value - maintenance) / amount ]

OR

"Zhoutonging price" = current bid - [ (net value - maintenance) / amount ]

Amount is
amount bought + BTC margin
for a long position.

amount sold - BTC margin
for a short position.

The brackets are implied by standard order of operations.

The square brackets aren't needed because of order of math operations - division always comes before addition/multiplication.

Edit: Gah, beat me to it :D

Wow, this insomnia is killing me.

Correct me if I am wrong, but from my experience margin% = 100 / Leverage.  So if I have 10:1 leverage selected my margin % should be 10% and not 4%.  I am not complaining or anything...

3 measurements to avoid beeing zhoutonged:

1. make use of STOP-LOSS orders! beeing stoped out with little loss can be really nasty some times, but it saves your butt most of the times!
2. don't over leverage and don't be greedy. there is no 100% probability of any movement - do wise riskmanagement!
3. in case you are still sure your position is right but face the zhoutonging price more and more: if you are SHORT exchange TO BTC, if you are LONG exchange to USD to minimize zhoutonging risk! (the ration of your deposit will have a big influence on your zhoutonging-risk because when you are short, e.g. your deposit increases the more BTC you hold in comparison to USD, so you can minimize your risk; but be warned that such hedges also reduce your overall profit (but since i suppose you NEVER EVER CONSIDER speculating leveraged with all your BTCs or USD you may find this advice usefull )

greets, gewure

could someone walk me through how to download it (on Safari if that makes a difference), I went to http://dl.dropbox.com/u/1127246/bitcoinica.user.js & see the script but have only ever downloaded things by pressing Download here buttons before, I could save it (the page?) & try & open it or something by I expect that's not how it works, sry for my tech noobness & thanks for any help

just drag and drop that file you downloaded into your browser it should install.   if you are using firefox you will need greasemonkey extension.

nope I'm using Safari on  Mac & when I save the page it's just a webachive & doesn't do anything but display the same page of code as the original, I tried dragging it in to Apps & on to the browser but just the same, so I guess that I need to be using either Firefox with greacemonkey extension or Chrome to make it work, by walk through how you do this I mean for someone who only downloads via clicking the download now button on sites & knows next to nada about how the Internets & computers works, i.e. one of the non geeky 99%

Otoh: Safari has no greasemonkey support and afaik extension that can give it this support does not exists. There are some SIBML hacks reportedly, but there are ugly and harder to do by non-geek than just installing Chrome.

I could probably make this as Safari extension, but I don't know how to do that unfortunately.

many thanks, I have Firefox + greacemonkey & Chrome, just haven't been using them hardly since I moved to Mac for the first time a couple of months ago & tend now to just stick with Safari because my Bookmarks are there & don't migrate/update to FF or CRM except for when I first loaded those browsers & are now out of date for my needs, I like the extensions available in FF a lot but have got used to having the bookmark folders above the tabs bar now & find them even more useful, I will check it out on Chrome tomorrow - thanks again

here ill make things easy for you.  i prefer firefox mainly bc chrome has terrible adblock support.  it is really easy to transfer your bookmarks, and honestly you should get out of safari.  here are some steps to get the above to work and a few extra to keep you secure and safe, i had quite a scare last night because my roomate stupidly downloaded a virus and was afraid it could have captured my mtgox passwords and such.

1.  download firefox  http://www.mozilla.org/en-US/firefox/new/

2. import safari bookmarks
-hit the orange firefox button > bookmarks > show all bookmarks
-a window will appear and browse to import and backup > import data from another browser

3. download these extension:
-greasemonkey: https://addons.mozilla.org/en-US/firefox/addon/greasemonkey/
-web of trust: https://addons.mozilla.org/en-US/firefox/addon/wot-safe-browsing-tool/
-adblock plus: https://addons.mozilla.org/en-US/firefox/addon/adblock-plus/
-you can now drag and drop the zhoutonging price script into the broswer and it will install

4. to secure/encrypt your saved passwords
- firefox button > options > options
- create a master password
https://i.imgur.com/PxCFU.png

PS you can easily change the location of your tabs/bookmarks bar in firefox.

many thanks

yep, I do have FF & added all the add ons that I enjoyed with my old Windows comp, then imported the bookmarks from Safari which has them in neat folders which is what I really liked, so I guess I'm best deleting FF & reinstalling to then get the whole new Safari bookmarks & folders imported, not sure once I do that I can keep adding folders though or adjusting their contents - will need to check it out again & it means that I'll have to install all the FF add ons again I guess

re 3 - thanks again I shall also add web of trust, the others already

re 4 - I use LastPass Pro with a Yubi key so that's covered

re PS - yep, I don't mind where it is, I just want to be able to keep sets of bookmarks in folders like Safari does

Many thanks again for helping me try & work this out, tomorrow i'll reinstall FF & try out the BTC Zhoutonging warning script, though hopefully not in rl

Thank you Zhou.!