Generally, you need to make a choice to apply the small business CGT concessions by the day you lodge your income tax return for the income year in which a CGT event happened, or at a later date if the Commissioner grants you an extension to make the choice.

Your income tax return may be enough evidence of the choice you've made. However, the retirement exemption requires you to keep a written record of the amount you choose to disregard. You also need to keep evidence to show the contribution you’re required to make (if any) to your super fund or RSA.

The small business 50% active asset reduction applies automatically if the basic eligibility conditions are satisfied and you haven't specifically chosen not to apply it.

Remember, you must keep records relevant to working out your capital gain or loss for 5 years after the year the CGT event occurs.