Bitcoin Forum

There is a robot that executes very small trades apparently to astroturf the mtgox last trade price.  My question is why would someone spend perfectly good money to do that?

To make you post this question.

A lot of merchants set their exchange rate based on the current best bid at Mt. Gox bid, or on Mt. Gox last.  So if you are buying something of a larger value from a merchant that uses best bid as the rate, then it usually is worth the money to narrow the spread a little.  You can trade a few pennies on Mt. Gox and as a result maybe save a few dollars (or a lot more) by getting a better price quote from the merchant.

Coinbase is one such bitcoin seller that uses best bid.

I was thinking there would be a service by now that one could pay and it would attempt to raise the best bid.   Maybe someone has done this and that's what you are seeing.

I get your point, but this penny bot looks to me like it's making the last trade look as low as possible.  I just can't think of a situation where this would be good for someone. After some thought, maybe this is Satoshi Dice keeping their BTC exposure to a minimum in real time.  If so, pretty cool demonstration of the technology.

Whatever it is, it's annoying as hell, and undoubtedly a negative presence given that it presents a false picture to any widgets that use the "last price" as the quote.  Its action reminds me of the way the tape is sometimes painted on pinksheet stocks.  I'd like to meet the author and punch him.  Even if it's Satoshi.

Maybe its just someone patiently unloading a ton of bitcoins while minimally affecting the market.

The lesson is - don't use last price. It is a bad indicator of the current value for several reasons, this being one of them.

Much better is to take some value (e.g. 100 BTC), see how much it costs to buy 100 BTC with the current depth table, how much is obtained by selling 100 BTC, and take the average.

right now, the btcusd spread is 4 cents.
if you disapprove of a bot marking the price at the lower end of that range, just put .01$ bids in midspread or higher.
better yet, make a bot that buys .01$ at market every so often.

or just place a 1BTC order .0001btc above the bid to collect cheap bitcoin!

Heres the behavior of the penny bot(s):
http://i47.tinypic.com/2sbtu91.png

The "buy a penny" bot looks turned off

Also in the volume chart it looks like someone bought 20k btc at 2 then sold them at 4. Also total buy volume has just recently surpassed sell volume for the first time since the hack.

To clear up any confusion:

Whether it is a buy or sell is available from mt gox once they revamped after the hack. That is what the colors mean. "Asks" are sells (Red) and "bids" are buys (Green).

For example in this trade we can see: "trade_type":"ask"
https://mtgox.com/api/1/BTCUSD/trades?raw

Thanks for the metrics, bitcoinbitcoin113.  That's interesting because whenever I look in realtime, I never see the bot buying, always selling.

I suppose we could also let MtGox know that this bot is undermining the MtGox brand, to the extent that their "last price" quote is widely perceived as untrustworthy.  Perhaps eventually they would amend their TOS so that polluting transactions are forbidden.

now where the hell do you get that notion from?
there'es penny-traffic on an unregulated exchange ZOMG!

give me seventeen good reasons why you consider this "undermining" and why the resulting price is "untrustworthy".



(hint: it's not)

Thanks for the hint.  But it's unnecessary.  I've traded millions on illiquid markets over many years and am perfectly capable of forming my own opinion wrt. the trustworthiness of quotes and the manipulation of price data.

MtGox is not an unregulated exchange.  It is regulated.  By MtGox.  It's a private enterprise which can set whatever rules it wishes for itself.  Including setting a minimum transaction size so as to encourage more price transparency and discourage painting the tape.

If the bot behavior wasn't perceived as outside of normal bounds, there wouldn't be gazillions of posts across many threads asking why the bot is doing what it's doing.

If the last price is always reset to be the bid price, then by definition the last price quote is superfluous and untrustworthy.  Might as well get rid of it altogether.

My opinion is that a 0.01BTC bot does not add any meaningful liquidity, but it does add a meaningful amount of noise, and if I was Mark Karpeles I'd view such a bot not as an asset, but a liability.  Sorry if this opinion offends you.  I don't think that's it's an outrageous or crazy viewpoint

I did not request that the SEC (or Japanese equivalent) regulate MtGox.  I merely stated an opinion, as their customer, that their quote data is an asset which they should value and take care of.  And that if it becomes overly polluted with noise and dust, it will reflect badly on their brand and will give people yet another reason to crave alternative exchanges and alternative quote feeds.

I love exercising my right as a consumer to complain to MtGox about annoying bots (or anything else).  

And you, as a bot owner, have the right to think that bots are wonderful.  But please don't disguise your posts as impartial, or try to silence valid opposing voices with non-sequiturs like demanding 17 justifications for a viewpoint, or that people go to the expense of writing their own bots to battle the original bot.

Are you serious?

If their transactions are DDoSing Mt Gox servers, if they're bypassing paying fees, then ban them.

But just trading a penny isn't something that should be banned. It is a *slight* liability, but the negative PR from mt gox banning a trade bot is going to be orders of magnitudes higher.

n8rwJeTt8TrrLKPa55eU just misses the glory days of may-june 2012 when users of mt gox were free of the penny bot plague.  :D This thread should be more about what the possible purpose of doing this is, I really have no idea and the other explanations don't really satisify me after seeing the buying pennies bot as well.

My bot only serves one purpose: Liquidating the BTC my business takes in - with minor effect on the market price. I do not ever place a limit that hits another order.

And only because someone cannot figure out WHY somebot is doing something, it doesn't make it "untrustworthy" or "a liability". This only goes to show that people fear what they cannot understand.

The Pennybot likely doesn't add any meaningful liquidity, but I would *probably think* that that isn't its purpose. Since it also doesn't change the QUOTE of the market, why should it bother you that there's traffic on the exchange? This has fuckzero to do with "price transparency". It has everything to do with "free market".

Can someone explain to me what a "Pennybot" is?

I think it refers to a bot that seems to be trading insignificant (~ penny) amounts to accomplish some aim.  That aim might be, for instance, to knock the "last" trade price to sit near the highest bid side of the spread. Or it may be to make sure there is a bid sitting just below the ask price, causing a real narrow spread.  When the amounts trade at a penny or less even, the purpose obviously isn't authentic, real buying and selling of positions but to manipulate the highest bid, lowest as or last trade quotations.

The bot I used to use (aricie) made microtransactions like that, and (despite common belief, apparently) it had nothing to do with market manipulation.

Basically, large amounts of trades with small amounts of money allow you to "scalp" small amounts of steady profit without a lot of risk exposure (if the price tanks outside of your "trading band", the bot can cancel open/unresolved trades without you taking much of a profit loss).  It actually works pretty well.



an illustration stolen from my bots site showing the trading strategy (the parameters are adjustable):

https://dnnbitcoin.aricie.com/portals/0/images/DnnBitcoinTradingBand.png


At any given time, my bot would have 20 or more open orders for trivial amounts (at one point, it was floating 80 open trades).  Those orders would get fulfilled, changed, or cancelled as the price fluctuated to preserve profit (by taking losses where neccessary) or to gain profit (with successful trades).







tl;dr:  It is not price manipulation, it is a trade strategy.  There is no conspiracy.

it would still be possibly or even easier to make fake depth

I guess the penny bot is run by some merchant that wants to increase the $$ he gets by devaluing the ɃɃ's last trade by a small amount. Maybe several people trying to front-run the very predictable penny bot can close the spread a bit. For sure these front-runners would have an incentive to do so. No need for regulations from MtGox.


Oh, how I wish this was used more.

Am I right in reading that this bot made you 200Btc ? nice

I'm so tempted to try and write a bot but I know it will end in tears as im not great with the old programming and it would have to compete.