我的理解
PR买转售HDB,可以马上买私人公寓,但不能住公寓,要至少住HDB满5年。
住满5年就可以出租HDB了。
http://www.hdb.gov.sg/fi10/fi10201p.nsf/WPDis/Buying%20A%20New%20HDB%20Flat%20(e-Sales)Policies%20-%20Conditions%20after%20Purchase?OpenDocument&SubMenu=Policies
Subletting
You can sublet your whole flat after the 5-year minimum occupation period. However, prior approval from HDB must be obtained before subletting of your whole flat.
这个是公民买新屋的情况, PR买转售HDB相信也是一样的要求。