Quote from: oda.krell on April 26, 2013, 02:38:54 PM

Quote from: crazy_rabbit on April 26, 2013, 06:46:38 AM

There could have always been someone who entered an order opposite you at just the same time, it never had a chance to appear in the order book because you bought it so fast.

Good point. That seems the most likely explanation to me at the moment.

The bitstamp trading interface is a bit limited. You place an order somewhat blind because you can't really see a live version of their order book in the buy/sell screen.

One caveat: If the scenario played out as described by crazy_rabbit, then that can only mean that bitstamp matches orders "internally" before putting them in the order book.

In detail, it had to work something like this:

(1) order book contains, and shows, 152/153 (bid/ask).

(2) OP places "buy" limit order at 170, but the order isn't put into the order book yet, but kept in a "temporary storage".

(3) Within very short time after (2), someone places new "sell" order. Bitstamp matches OP's limit buy with the new (market or limit) sell, at 170, since OP's order was "on the market" before. The actual bids never appear in the order book, only the executed order will be listed afterwards.

Someone correct me please if I got something wrong here, but that's how it makes most sense to me.

I think the web interface isn't always 'up to date' with the backend. I definitely have seen orders on either side of the orderbook that far overlapped the other side of the book. It might be by design that the web frontend updates when it can, rather then constantly so as to not bottleneck the core trade engine. It would be interesting to see if by API access there is the same lag.