<P> On 1 July 2003, the Building & Development Division of HDB was corporatised to form HDB Corporation Pte. Ltd . (HDBCorp). HDBCorp was later renamed Surbana Corporation Pte. Ltd . HDB's headquarters were moved from Bukit Merah to its new premises at the HDB Hub at 480 Lorong 6 Toa Payoh on 10 June 2002 . </P> <P> The existing Bukit Merah premises, known as Surbana One, became the headquarters for Surbana Corporation Pte. Ltd . </P> <P> HDB employees are organised under a house union, HDB Staff Union (HDBSU). The union is an affiliate of the National Trades Union Congress . </P> <Table> <Tr> <Th_colspan="5"> HDB new flats programmes </Th> </Tr> <Tr> <Th> Programmes </Th> <Th> Abbrev </Th> <Th> Start </Th> <Th> End </Th> <Th> Remarks </Th> </Tr> <Tr> <Td> Registration for Flat </Td> <Td> RFS </Td> <Td> 1980s </Td> <Td> Feb 2002 </Td> <Td> Any surplus units from BTOs, balance BEs or HDB buy - back schemes through balloting method </Td> </Tr> <Tr> <Td> Walk In Selection </Td> <Td> WIS </Td> <Td> Mar 2002 </Td> <Td> Feb 2007 </Td> </Tr> <Tr> <Td> Mthly / Qtrly / Hyrly / Balance Sale </Td> <Td> E-Sale </Td> <Td> Apr 2007 </Td> <Td> - </Td> </Tr> <Tr> <Td> Balloting Exercise </Td> <Td> BE </Td> <Td> Aug 1995 </Td> <Td> - </Td> <Td> Only available for initial large surplus units of SERS </Td> </Tr> <Tr> <Td> Build - To - Order (HDB) </Td> <Td> BTO </Td> <Td> Apr 2001 </Td> <Td> - </Td> <Td> Buying a new flat with a waiting period of 4 years </Td> </Tr> <Tr> <Td> Design, Build and Sell Scheme </Td> <Td> DBSS </Td> <Td> Oct 2006 </Td> <Td> - </Td> <Td> Buying a new condominium design flat built by private developer </Td> </Tr> </Table>

When was hdb formed and what was its role