The effective rate is 10%. Section 115 - 10 of Income Tax Assessment Act 1997 (ITAA 1997) states that a complying superannuation fund is entitled to a discount capital gain. Section 115 - 100 (b)(i) states that the discount for a complying superannuation entity is 33 and a 1/3%.
To be eligible for a discount the asset must have been held for more that 1 year, Section 115 - 25 ITAA 1997.
For example, if a Superannuation Fund purchases a parcel of shares for $20,000 and sells them 1 year later for $30,000 you will have a gain / profit of $10,000.
Of the $10,000 a 1/3 discount is provided or 2/3 is taxable, i.e., $6,666.66 The income tax rate for complying superannuation funds is 15%. Therefore the liability is $1,000 ($6,666.66 x 15%).