The legislation containing the core rules for the simplified imputation system was introduced into Parliament on 30 May 2002. The initial Acts were:
- New Business Tax System (Imputation) Act 2002
- New Business Tax System (Over-franking Tax) Act 2002
- New Business Tax System (Franking Deficit Tax) Act 2002
The Bills were passed on 27 June 2002, and received royal assent on 29 June 2002. These Acts introduced the core rules for the new simplified imputation system which took effect from 1 July 2001.
The new rules are contained in Part 3-6 of the ITAA 1997 and replace the former imputation provisions contained in Part IIIAA of ITAA 1936 which ceased to apply after 1 July 2002.