hello, question about trading

[irongym]

Hello,

First, sorry for my english.

Imagine this is the order book on btc-e:


SELL                                  BUY

1 btc at 230            1 btc at 220
1 btc at 240            1 btc at 210
1 btc at 250            1 btc at 200

now, in same time

 mister A put a SELL order of 2 btc at 10 euros      AND     and mister B put a BUY order of 2 btc at 250

at what price mister a will sell is 2 btc?
at what price mister b will sell is 2 btc?

in advance thanks

[BlackSpidy]

Mister A will definitely sell his 2 bitcoin at 10 euros, minutes (maybe seconds) after placing his sell order.
Mister B will buy 2 bitcoin at a $250, quickly. Mister A is selling his bitcoin cheap. He will sell them easily quickly in the market. Mister B said he wants to buy bitcoin at $250 (more than market price). He will find someone selling at that price easily.

Think of bitcoin like you do gold. Some people sell gold for cheap, some people sell gold with a value above market price. If someone sells you a $1 (real) gold ring, you can sell it for $0.5 or $2. The price you ask for bitcoin is up to you (to buy or sell). The price people will actually buy/sell bitcoin at depends on the market's whim.

[DannyHamilton]

Please disregard BlackSpidy's response.  He clearly doesn't understand the question.

[el kaka22]

I think that the sell order of 10 euros will be executed at 220 and 210, and the 250 order will be executed at 230 and 240. It is because the exchange will find the best orders to fill up your buy/sell, and if there isn't a buy/sell suitable for your order (like one at 225), then it will create a new order at the orderbook.

[BlackSpidy]

Please disregard BlackSpidy's response.  He clearly doesn't understand the question.

So, it's a question about btc-e? Because this looks like a general question about how exchanges work. Also, I'd like to know why I'm wrong in the matter.

[irongym]

ok but if

SELL                                  BUY

1 btc at 230            1 btc at 220
1 btc at 240            1 btc at 210
1 btc at 250            1 btc at 200

now, in same time

 mister A put a SELL order of 2 btc at 10 euros      AND     and mister B put a BUY order of 2 btc at 250 AND MISTER C put SELL ORDER 1 BTC at 20 euros and mister D a buy order of 1 btc at 245

I think that the sell order of 10 euros will be executed at 220 and 210, and the 250 order will be executed at 230 and 240. It is because the exchange will find the best orders to fill up your buy/sell, and if there isn't a buy/sell suitable for your order (like one at 225), then it will create a new order at the orderbook.

[DannyHamilton]

el kaka22 is correct.

Mister A's sell order will fill against the standing BUY orders.  He will receive 430 (215 per BTC) and will spend 2 BTC.
Mister B's buy order will fill against the standing Sell orders.  He will receive 2 BTC and will spend 470 (235 per BTC).

The remaining order book will be:

Code:

SELL                    BUY

1 BTC at 250          1 BTC at 200

[DannyHamilton]

ok but if

SELL                                  BUY

1 btc at 230            1 btc at 220
1 btc at 240            1 btc at 210
1 btc at 250            1 btc at 200

now, in same time

 mister A put a SELL order of 2 btc at 10 euros      AND     and mister B put a BUY order of 2 btc at 250 AND MISTER C put SELL ORDER 1 BTC at 20 euros and mister D a buy order of 1 btc at 245

I think that the sell order of 10 euros will be executed at 220 and 210, and the 250 order will be executed at 230 and 240. It is because the exchange will find the best orders to fill up your buy/sell, and if there isn't a buy/sell suitable for your order (like one at 225), then it will create a new order at the orderbook.

The orders will not be "at the same time".  The exchange almost certainly uses an order queue.  Therefore, the orders will be processed in the order that they are received.  If any orders are received at the EXACT same time, then the queuing system will chose the order that they will be processed.

Lets assume that they are queued in the order that you describe them.

Mister A's sell order will fill against the standing BUY orders.  He will receive 430 (215 per BTC) and will spend 2 BTC.
Mister B's buy order will fill against the standing Sell orders.  He will receive 2 BTC and will spend 470 (235 per BTC).
Mister C's sell order will fill against the remaining BUY order. He will receive 200 and will spend 1 BTC.
Since there aren't any remaining Sell orders on the order book that qualify to fill Mister D's Buy order, Mister D's order will be added to the order book and will wait for sell orders to fill it.

The remaining order book will be:

Code:

SELL                    BUY

1 BTC at 250          1 BTC at 245

[irongym]

Sorry but it s not look logic cause when mister b will buy his 2 btc for 250 the real order book will be:

SELL                                  BUY
2 btc at 10 euros <--mister a order
1 btc at 230            1 btc at 220
1 btc at 240            1 btc at 210
1 btc at 250            1 btc at 200

so why he will not buy 2 at 10 euros?
and same for inverse:

SELL                                  BUY
                            2 btc at 250 euros <--mister b order
1 btc at 230            1 btc at 220
1 btc at 240            1 btc at 210
1 btc at 250            1 btc at 200

why mister a will not sell for 250?

el kaka22 is correct.

Mister A's sell order will fill against the standing BUY orders.  He will receive 430 (215 per BTC) and will spend 2 BTC.
Mister B's buy order will fill against the standing Sell orders.  He will receive 2 BTC and will spend 470 (235 per BTC).

The remaining order book will be:

Code:

SELL                    BUY

1 BTC at 250          1 BTC at 200

[BlackSpidy]

  So, buy orders automatically fill against sell orders, on btc-e? Is this standard practice across lots (or all) of exchanges? I thought it would end up looking this:

SELL                                                              BUY
2 btc at 10 euros <--mister a order                1 btc at 220
1 btc at 230                                                1 btc at 200
1 btc at 240                                                2 btc at 250 euros <--mister b order
1 btc at 250              



(then orders match)                                                                
SELL                                                              BUY
2 btc at 10 euros <--mister a order                1 btc at 220
1 btc at 230                                                1 btc at 200
1 btc at 240                                                1 btc at 250 euros <--mister b order
0 btc at 250              

[jeannemadrigal2]

A really good way to get a handle on the order books is to watch them fill on the exchange.  You will see the trade gap get bigger and smaller, and when orders are placed at market value you can see them eat up the best offers on the books.  At least for me this was the best way to get a handle on it.  Also some charts have a "depth" chart which is another way to interpret the order books.

[GreenStox]

Hello,

First, sorry for my english.

Imagine this is the order book on btc-e:


SELL                                  BUY

1 btc at 230            1 btc at 220
1 btc at 240            1 btc at 210
1 btc at 250            1 btc at 200

now, in same time

 mister A put a SELL order of 2 btc at 10 euros      AND     and mister B put a BUY order of 2 btc at 250

at what price mister a will sell is 2 btc?
at what price mister b will sell is 2 btc?

in advance thanks

mr a will sell the 2 btc at 10 €

mister B will buy 2 btc at 250€

The order executes at the price specified, however since the highest bit and lowest ask needs to reach that level, until then the current one will be in from of MR A and MR B 's order.

Thats how the price auction mechanism works.