Simply put, the fixed cashback forex rate (linked exchange rate system) forexrebatenetwork both for historical reasons and to stabilize the exchange rate and curb speculative activities What is forex rebate bestforexrebate initially as a British colony, the currency is with the pound peg later because the pound depreciated too quickly after the dissolution of the gold standard, change with the U.S. Whatisforexrebate peg You ask why later not open the Hong Kong dollar free exchange? Because Hong Kongs economy is small, and high liquidity (by the end of the last century, Hong Kongs economy has been dominated by the financial sector), if the free exchange of Hong Kong dollars will certainly fluctuate significantly, will be a serious blow to the Hong Kong economy (Southeast Asian financial crisis), so the Hong Kong dollar using a fixed exchange rate Well, the above are not related to the question long-winded paragraph is to answer a little longer this question my understanding is very simple: 1. Cost initially the British wanted to send the British pound directly in Hong Kong, did not get up because the people have silver dollars, not willing to change the European Union also has several countries did not adopt the euro, but retain the original currency but participate in the ERM2 mechanism, will be fixed to the euro exchange rate to obtain some of the benefits of joining the euro zone such as Denmark 2. Hong Kong dollar tight currency can change the fixed exchange rate policy itself can also change this in monetary policy when the situation changes Give the authorities a way back when the pound is soft, the Hong Kong dollar can be exchanged for U.S. dollars in the future may one day be replaced by a tightening of the yuan (of course, more likely to be pushed by Beijing to directly adopt the yuan) if the dollar directly, the way back is gone if the dollar suddenly rose and fell how? If you need to use the monetary policy how to do?3. directly with the dollar there is nothing to this and the European Union with the euro is not the same EU countries unified currency or for political federalization preparations (to promote population mobility, unified national banking sector, and ready to unify national finances) for Hong Kong the value of the Hong Kong dollar is the main demand; linked exchange rate system will be able to achieve the purpose