You treat each batch of shares purchased independently. If you buy 100 ashes on August 1st and 200 shares on October 1st and sell the 300 on September 1st the following year, then the first batch of 100 qualifies for the discount, but not the other batch of 200. This assumes both have made gains.
From a practical point of view, when several batches bought have different CGT implications (some are at a loss, some qualify for the discount and some don’t), but all are sold together in one transaction, you must apportion the sale proceeds over the three purchase quantities. For example if you bought 100 shares at $1 each over a year ago, 200 at $2 each under a year ago and 300 at $4 each under a year ago and sold the 600 at $3 each, then the first batch qualifies for the discount, the second doesn’t and the third is a loss (in which case the purchase date doesn’t matter). Say the sale brokerage is $60, so the net proceeds is $1,740. For calculating the CGT, apportion these against the three cost bases, so for the first batch the sale proceeds are $290, the second $580 and the third $870. With regards to the first batch, even though it qualifies for the discount, at this stage you don’t apply the discount until you have allocated all carry forward and current year losses against your capital gains. You should first apply them agains your non discountable gains. If there are losses left over, apply those agains your discountable gains. Only the discountable gains left over get the discount.
Also, say in the above example, you just sold 100 shares instead of 600. You can chose which batch they apply to. They could apply to all of the first batch or just a hundred of the second or third. If you chose the second or third, then in that case you must apportion the cost base to match the sale quantity. So you would use a half or a third respectively of those two batches cost base. You would need to keep good records of what portion of each batch has been sold and what is left over. You can chose which batch or portion of a batch the sale applies to, to whatever is most advantageous to you.
