Previous studies on the office market tend to focus on either the rental market or the aggregate sale market. This paper focuses on the intra-metropolitan sale market and the office price and trading volume dynamics in Hong Kong. Buildings with higher prices are not necessarily being traded more. Office prices of different categories do not necessarily move together. On the other hand, the trading volumes of the higher class tend to Granger cause the lower class, and this conclusion is robust to alternative classifications. It is in contrast to several existing theories and directions for future research are discussed.