Bitstamp TX Fee Exploit - Fee 1.16% instead of 0.2% [Bitstamp Fixes on May 15th]

[ninjabenja]

My typical 30 day trading volume is 300k at minimum.

And you didn't notice you were being ripped off?

If I had I would have been the OP. Shit happens. I guess that somehow as "obvious" as it must have been, none of the other handful of people who use stamp noticed it either. Our bad.

Still no reply to my comment on their facebook or the tweet I sent them.

[grahvity]

My typical 30 day trading volume is 300k at minimum.

And you didn't notice you were being ripped off?

If I had I would have been the OP. Shit happens. I guess that somehow as "obvious" as it must have been, none of the other handful of people who use stamp noticed it either. Our bad.

Still no reply to my comment on their facebook or the tweet I sent them.

Link to tweet? I will check quality and retweet.

[Cryptopher]

Ugh, rounding policies always cost the end user, which is fair enough provided that it is reasonable and can't be exploited. If something underhand is going on with the exchange in order to screw sellers then that is very concerning.

[porqupine]

If I'm not misunderstanding this - the OP's claim to fraud is not as regards to the rounding, but that Bitstamp is intentionally breaking up large orders into micro sized ones, in order to benefit from the rounding. The later would definitely be fraud if it were proven true.

[davout]

Has it always been this way or was there a recent change ?

It has always been this way.
And it's been written on their website as far as I can remember.

[dave111223]

The fix should be simple; don't allow orders to be input that generate a fee less than $0.01.

So as other have said; a $5 minimum order; which IMHO is very reasonable.  And this does not required any messing with the rounding/trading system which could be hazardous.

[davout]

People, please stop being dumb and suggesting retarded fixes.
The correct fix is to learn how to fucking count with more decimal places.

[dreamspark]

Has anyone had a reply from support or Hazek that has contacted them?

[mrnejc]

The fix should be simple; don't allow orders to be input that generate a fee less than $0.01.

So as other have said; a $5 minimum order; which IMHO is very reasonable.  And this does not required any messing with the rounding/trading system which could be hazardous.

Mimimum orders are not a solution. Sell/buy orders are not always done in whole but can get split up.

See this example:

• seller A and B are each selling 1 BTC
• I place my order for 1.00001 BTC
• my order is executed in 2 steps:
  
  • buy 1 BTC from seller A
  • and 0.00001 from seller B
  fee is calculated for each transaction independently and this is where error occurs - minimum order size was in place, but still
  

As other said - they should calculate fee to 5, maybe even 8, decimals – everyone (except Bitstamp) gets happy, but then again happy customers – happy CEO …

[dave111223]

The fix should be simple; don't allow orders to be input that generate a fee less than $0.01.

So as other have said; a $5 minimum order; which IMHO is very reasonable.  And this does not required any messing with the rounding/trading system which could be hazardous.

Mimimum orders are not a solution. Sell/buy orders are not always done in whole but can get split up.

See this example:

• seller A and B are each selling 1 BTC
• I place my order for 1.00001 BTC
• my order is executed in 2 steps:
  
  • buy 1 BTC from seller A
  • and 0.00001 from seller B
  fee is calculated for each transaction independently and this is where error occurs - minimum order size was in place, but still
  

As other said - they should calculate fee to 5, maybe even 8, decimals – everyone (except Bitstamp) gets happy, but then again happy customers – happy CEO …

And I don't think anyone is going to matter much if there are remainder orders which are less than $5; as it's hard to abuse the system in this manner.  Whereas the current system allows to put in repeated tiny (less than $1) orders.

It doesn't matter if you occasionally get screwed for a couple of $0.01 fees the problem is when this is done repeatedly and consistently so that the amounts add up to huge fees (such as in the OP where clearly someone is placing 100s of $0.86 orders these are not remainders).

People, please stop being dumb and suggesting retarded fixes.
The correct fix is to learn how to fucking count with more decimal places.

Because changing your entire decimal precision could cause unintended bugs....
This kind of change would take months of testing before live implementation for an exchange of bitstamp size.

Where as order limit could be implemented overnight with no chance of serious (money losing) bugs.

[davout]

Because changing your entire decimal precision could cause unintended bugs....

As opposed to what? Intended bugs?
Just because something is inconvenient or hard does not mean it should not be done, applying half-assed pseudo band-aids is exactly what you should not do.

When you have zero experience in a field, and no valid point to make, your best course of action is usually to refrain from talking.

[mmitech]

People, please stop being dumb and suggesting retarded fixes.
The correct fix is to learn how to fucking count with more decimal places.

well tell me how would you collect a $0.001 ?

[smooth]

People, please stop being dumb and suggesting retarded fixes.
The correct fix is to learn how to fucking count with more decimal places.

well tell me how would you collect a $0.001 ?

It was explained upthread. Charge the account balance 0.001, round balances down to the penny when withdrawing.

[zetaray]

Fees should be charged per buy or sell order, not by each split up transaction. It will not be difficult to change it. Having developed an exchange, changing fee structure should be trivial. Bitstamp do not want to make changes because they will make less money from fees. The only way to pressure them to make modifications is to stop using Bitstamp.

[davout]

Fees should be charged per buy or sell order, not by each split up transaction. It will not be difficult to change it. Having developed an exchange, changing fee structure should be trivial.

Think more, I already gave the correct solution.
What you're suggesting is strictly equivalent to charging the fee at the transaction level, that is because you need to be able to handle partial fills properly.

[Boxman90]

I have received a response from Bitstamp. I request that you all re-read my starting post, as I changed it to better reflect the situation as it is.

Bitstamp did reply to my inquiry about their transaction fee calculation.

The rounding up which occurred in your case was in accordance with our notice provided in the Fee schedule section of our website. Fiat currencies, unlike Bitcoin, have two decimal places, therefore the smallest fee Bitstamp can charge for its services can never be below $0.01.

Bitstamp does not sell or buy bitcoins nor does it manipulate how orders are executed. If a sell was executed for one client (you in this case) this means that another Bitstamp client had his buy order executed on the opposite side of the trade.

As you are probably aware that "If you try to commit an order with price greater or lower than 20% of the current market price, our system will ask you for additional confirmation." (available in our FAQ: https://www.bitstamp.net/faq/). Due to such actions, it is sometimes possible that a user can perform a trade which is lower than $1 in value when placing an order which is higher than the market price at the time when it was executed.

They further explain their rounding policy, which is fine, but did not explain (yet) why the order limit is then not $5 so that the exploit as mentioned in this post cannot happen. The fact remains that an order limit of $1 in combination with the rounding off to $0.01 causes any order of $1 or smaller to be charged five times the fee.

Whether or not the low $1 order limit is intentional in order to harvest these fees or not, I will leave upon you (the community) to decide. The willingness of Bitstamp to change the order limit will show us as a community if it is intentional or not.

[dreamspark]

I have received a response from Bitstamp. I request that you all re-read my starting post, as I changed it to better reflect the situation as it is.

Bitstamp did reply to my inquiry about their transaction fee calculation.

The rounding up which occurred in your case was in accordance with our notice provided in the Fee schedule section of our website. Fiat currencies, unlike Bitcoin, have two decimal places, therefore the smallest fee Bitstamp can charge for its services can never be below $0.01.

Bitstamp does not sell or buy bitcoins nor does it manipulate how orders are executed. If a sell was executed for one client (you in this case) this means that another Bitstamp client had his buy order executed on the opposite side of the trade.

As you are probably aware that "If you try to commit an order with price greater or lower than 20% of the current market price, our system will ask you for additional confirmation." (available in our FAQ: https://www.bitstamp.net/faq/). Due to such actions, it is sometimes possible that a user can perform a trade which is lower than $1 in value when placing an order which is higher than the market price at the time when it was executed.

They further explain their rounding policy, which is fine, but did not explain (yet) why the order limit is then not $5 so that the exploit as mentioned in this post cannot happen. The fact remains that an order limit of $1 in combination with the rounding off to $0.01 causes any order of $1 or smaller to be charged five times the fee.

Whether or not the low $1 order limit is intentional in order to harvest these fees or not, I will leave upon you (the community) to decide. The willingness of Bitstamp to change the order limit will show us as a community if it is intentional or not.

You should point them in the direction of davouts solution as well which is probably fairer.

Yes we know fiat currencies has 2 decimal places but a system can store more than two. Just use more decimal places and round on withdrawal.

[Anduck]

Has Bitstamp commented this thing at all? There are multiple ways to fix this... and being quiet makes it worse.

[Boxman90]

Has Bitstamp commented this thing at all? There are multiple ways to fix this... and being quiet makes it worse.

See https://bitcointalk.org/index.php?topic=597647.msg6590228#msg6590228

[davout]

Has Bitstamp commented this thing at all? There are multiple ways to fix this... and being quiet makes it worse.

Actually there happens to be a single correct way to fix it.
For pretty much the same reason there is one single correct way to count.

Their answer is simply magical.