[R-SIG-Finance] correlation between two asynchronous time series?

[Michael]

Hi all,

If I want to find out the correlation between two time series, one is
the Hong Kong stock index, the other is the S&P 500. The two markets
open at two different time.

What impact it might have on my estimate of the correlation of the two
series? How do I address this asynchronous time series problem? Any
good models?

Thanks a lot!