Why analysts are more positive on office market in Singapore than in Hong Kong

Price correlation is weaker.

According to Barclays, contrary to the view that Hong Kong’s office prices will also fall 20% due to the high correlation of office prices with residential, this correlation in Singapore, historically, has been weaker. 

The correlation between Hong Kong and Singapore office prices is also weak at 43%. On a supply/demand fundamental perspective, we are relatively more positive on the Office space in Singapore.

Here's more from Barclays:

We expect prime office rents have hit an inflection point, and given the below-average annual supply of 0.85mn sqft during 2013-16 we expect more pricing power for landlords.

We expect Singapore office rents to grow +3%/10%/3% in 2013/14/15E. We see Office REITs as the best way to play the theme.