Q. Example on hedge fund?
Hedge Fund enters agreement to sell HK$ in six month's. At expiration the Hedge Fund requires to buy spot HKD and deliver these against the short future's position.
If the peg embraces the cost of replacing the HKD it has sold is fundamentally the 6 month differential between USD and HKD interest rates.
On Thursday August 20th the dissimilarity in inter-bank interest rates was about 6.3% Hong Kong rates being higher due to heavy demand for HKD loans which are needed to short the currency. Consequently a hedge fund manager making a USD 1 million bet Thursday against the HKD would have paid USD63000.
If the finance manager believed that the peg would break and thus the HKD depreciate say about 30% then the potential profit would be USD300000. Evaluated to the cost of making the trade USD63000 this is a good profit.