A demerger occurs when a company splits its operations into two or more entities or groups and distributes to its shareholders a direct interest in one or more of the parts. New tax rules applied to demergers from 1 July 2002. Broadly the tax consequences are:

  relief from capital gains tax (CGT) that would otherwise be payable as a result of the demerger transaction;

  the cost base in the original interest is spread between the original interest and the interest in the demerged entity (based on the relative split in market values); and

  an exemption from the provisions that would otherwise treat the shareholder as having received a taxable dividend from the transaction, subject to specific anti-avoidance rules.

  any pre-CGT interests retain their pre-CGT status.

 Key tax relief criteria

 A selection of recent demergers and their key features is detailed below. As a general rule the following applies to individual taxpayers (unless they acquired their shares under an employee share scheme) who are Australian residents for tax purposes, who acquired their shares after 19 September 1985 and who hold shares as an investment asset rather than as trading stock.

To qualify for tax relief the key criteria are:

The underlying ownership of the demerged entity must be maintained. (The ATO will examine the proportional interests and market values of ownership interests.)

The Head Entity must divest at least 80% of its ownership interests in the demerged entity. This is to ensure that only ‘genuine’ demergers are able to obtain the tax relief. (Importantly, demerger relief will not be available for disposals of the remaining ownership interests at a later date.)

Shareholder action

The Head Entity will normally advise shareholders if it has undertaken an eligible demerger and shareholders should be aware that:

they may be entitled to choose rollover relief (see below) for any capital gain or loss

they are required to calculate immediately after the demerger the cost base and reduced cost base of their interests in the Head Entity and their new interests in the Demerged Entity

Rollover relief

If shareholders choose rollover relief:

any capital gain or loss is disregarded

the new interests are acquired on the date of the demerger. (Note that if a proportion of your original interests was acquired before 20 September 1985 (pre-CGT), the same proportion of the new interests is treated as pre-CGT assets)

If shareholders do not choose rollover relief:

any capital gain or loss cannot be disregarded

all of the new interests are acquired on the date of the demerger

A calculator at the ATO website helps shareholders work out the capital gains tax consequences under a demerger, including the BHP Billiton, CSR, Sonic Healthcare, Mincor and WMC demergers. It can be accessed here.

Below are a few demergers of the past twenty years. For the full table click on the link below this table.