Good point. As I write this, BTC-China is at 5680 RMB, or 932 USD. Bitstamp is 655 USD, Gox is 776 USD.
Maybe China is driving the demand and other exchanges are arbitraging against China. Since there's a lag in transferring funds into exchanges, the 20% to 40% premium in China may just be a measure of latency in a fast-moving market.
If so, then we'll see the prices converge over time, and we should use BTC-China as a leading indicator of exchange rates.
FWIW, if you are seriously into arbitraging, you won't keep transferring funds between both exchanges to finish the cycle of buying-selling. What you will actually do is having half of your funds on both sites and execute both operations on both sites at the same time to have them match.
Yep, that's the only way to do it with zero risk. But since btcchina.com is consistently higher than the other top exchanges you'll eventually have to move CNY out of there and bitcoin in. Moving bitcoin there is trivial (which shows how great bitcoin is) but moving CNY out and converting it to USD for the other exchanges is trickier (need a Chinese bank account for example) so I would expect the lag in price to continue.
Exactly, that's the point I've raised in another comment. By the way, I've read that Bobby Lee (CEO @ BTCChina) is already dealing with Chinese authorities to see if he can expand the business out of China (read: accept €/$). Can't wait to see this happen as well as seeing Litecoin integrated there.
Maybe China is driving the demand and other exchanges are arbitraging against China. Since there's a lag in transferring funds into exchanges, the 20% to 40% premium in China may just be a measure of latency in a fast-moving market.
If so, then we'll see the prices converge over time, and we should use BTC-China as a leading indicator of exchange rates.