Arbitrage is riskless profit of any kind. What kind of arbitrage are you wondering about? Interest rate? Exchange rate? With transaction costs and efficient global markets true arbitrage is nearly impossible.

This is the arbitrage I am most familiar with. They have to factor in whether the deal might fall trhough, whether there might be another bidder, etc. If its rock solid that there is no other bidder, the price will hold, and the deal will close, it is just a matter of the "time value of money". The arbitrage is just to give the seller his money today for a transaction that will close, and pay in cash, in the future. That difference should be on the order of the margin rate times the time difference.

There are other arbitrages, say seeing a low offer on a stock or currency in one market then turnaround and selling it at a better bid in another country or on another exchange. Of course once that is done the markets will often move back into alignment. I think it would be rare for an individual to regularly make money in such a fashion because the differences are rather small and the retail commisions and bid/ask spreads would eat up your potential profits.

I'm glad you liked that article. :)

Contingencies is a fantastic magazine and I highly recommend it to everyone. You can read it online:

http://www.contingencies.org/

I don't read articles because I already know it all.