# Last edited on 2014-06-11 23:41:47 by stolfilocal
# NOT POSTED

One can view arbitrage trading   

For example, suppose at exchange A the order book is 
   buy at ..., 440, 500 USD; sell at 520, 550, ...
and at echange B it is 
  buy at ..., 360, 380; sell at 400, 460, ...
all orders being 1 BTC.  Note that there is an overlap of bids at A and asks at B.  The arbitrager at A then sells one  BTC for 500 USD, his collaborator a B buys one for 400 USD; that leaves the spreads 440 -- 520 and 380 -- 460; with no bid/ask overlap, so no further arbitrage is possible.  The two together made a 100 USD profit, which (assuming a 450 USD current price) is already split between the two accounts.  If later the inverse situation occurs, they do the opposite trades, but together make a profit again.