One of the first questions people ask when they start trading or betting on Betfair is surprisingly simple: How big should my trading bank be? £100? £500? £1,000? £10,000? It sounds like a straightforward question. In reality, there is no sensible answer until you know something much more important: what is the bank expected to survive? A strategy with a 70% strike rate and average odds of 1.50 has a completely different risk profile from one operating at average odds of 12.0