Prior to the implementation of the BTO system, HDB relied on the Registration for Flats System to build flats according to the number of applicants on its waiting list. Since applicants were not required to make any down-payment, the number of applications received by HDB might not reflect the actual demand for new HDB flats. Indeed, the Registration for Flats System resulted in an oversupply of flats in the late 1990s when the housing demand plunged after the outbreak of the Asian financial crisis. It took HDB about five years or so to clear the stock of unsold flats.