As you said, XIN is a micro cap stock, so its price correlation with the market is not very high by using a intraday basis or daily basis. However, XIN's price does correlated highly to China mainland index and the S&P 500 on a monthly basis. If you compare XIN with Vanke on a 5 year frame, you will find their price movements are highly correlated. XIN just significantly underperform compared with Vanke.
The very strong correlation between XIN and Vanke, right up until the last week or so, should give all short term bulls reason to reconsider. The chart seems to lend pretty solid support to the theory that XIN's recent 40% pop was only due to being mentioned back to back in the WSJ and Motley Fool, rather than any improvement in XIN's business outlook.
Here's the headache causing problem for short term bulls: if we interpret the jump as being caused by an economic factor, at the same time we would have to explain why that improved economic factor helped XIN, BUT DIDN'T ALSO help Vanke.
No good explanation for that discrepancy leaps to mind, but I always keep an open mind.