List of SBF launches
Sale of Balance Flats, comprising unsold leftover flats from past BTO launches, surplus flats from SERS projects, old repurchased flats (including flats from some divorced or fiance couples), are done “when HDB accumulate sufficient flats“, usually twice per year, but this is NOT A RULE. Since 2010 the SBF exercise is done same day with a BTO launch.