Understanding Capital Loss Offsetting
When you sell an investment for less than you paid for it, you've made a capital loss. While nobody enjoys losing money, these losses have a silver lining: they can offset capital gains, reducing your overall tax liability. Understanding how this works is essential for every Australian investor.
The basic principle is straightforward—capital losses reduce capital gains. However, the rules around timing, ordering, and what can be offset are more nuanced than many investors realize.
The Fundamental Rules
Capital losses can only offset capital gains: Unlike some countries, Australia doesn't allow capital losses to offset ordinary income. If you have $10,000 in capital losses but no capital gains this year, you can't use those losses to reduce your salary income.
Losses must be applied in a specific order: Current year losses must be applied before carried forward losses. You must apply losses against gains before the 50% CGT discount is applied.
Unused losses carry forward indefinitely: If your losses exceed your gains in a given year, the excess carries forward to future years. There's no time limit on using carried forward losses.
The Order of Applying Losses
The ATO requires losses to be applied in this sequence:
- Current year capital losses are applied first against current year capital gains
- If gains remain, carried forward capital losses are applied
- Only after losses are applied do you calculate the 50% CGT discount on eligible gains
- The resulting amount is added to your assessable income
This ordering is important because it affects which gains the 50% discount applies to.
Practical Example
Let's say you have the following in the 2025-26 financial year:
| Transaction | Amount | Holding Period |
|---|---|---|
| Gain on Share A | $8,000 | 14 months (eligible for discount) |
| Gain on Share B | $4,000 | 8 months (not eligible) |
| Loss on Share C | $5,000 | 10 months |
| Carried forward loss | $2,000 | From FY2024-25 |
Step 1: Apply current year loss ($5,000) You can choose which gains to offset first. Strategically, offset the non-discounted gain:
- Share B gain reduced from $4,000 to $0, using $4,000 of loss
- Remaining $1,000 loss applied to Share A, reducing gain to $7,000
Step 2: Apply carried forward loss ($2,000)
- Share A gain reduced from $7,000 to $5,000
Step 3: Apply 50% CGT discount to eligible gains
- Share A (held >12 months): $5,000 × 50% = $2,500 assessable
Result: $2,500 added to your taxable income (instead of $12,000 gross gains)
Strategic Considerations
Choose which gains to offset: You have flexibility in which gains you apply losses to first. Generally, it's more tax-efficient to offset gains that don't qualify for the 50% discount.
Timing of realizing losses: Consider whether to realize a loss this financial year or next, depending on your expected gains in each period.
Don't let losses expire: While losses carry forward indefinitely, there's an opportunity cost to waiting. Consider whether accelerating gains makes sense.
Watch for wash sale issues: Don't sell purely to crystallize a loss with the intent to immediately repurchase. The ATO can disallow losses from wash sales.
What Counts as a Capital Loss?
Capital losses arise from the disposal of a CGT asset. This includes:
- Shares and ETF units sold for less than cost base
- Investment property sold at a loss
- Collectables worth more than $500 (with restrictions)
- Cryptocurrency disposed of at a loss
- Managed fund units redeemed below cost
Your cost base includes not just the purchase price but also:
- Brokerage and transaction costs
- Incidental costs of acquisition and disposal
- Non-deductible holding costs (for property)
Common Mistakes to Avoid
Forgetting carried forward losses: Review previous years' tax returns to ensure you're claiming all available carried forward losses.
Incorrect cost base calculations: Ensure your cost base includes all legitimate costs, including brokerage both when buying and selling.
Missing the ordering rules: Remember that losses are applied before the CGT discount calculation.
Not keeping records: Maintain detailed records of all capital losses, including those carried forward, for at least five years after they're fully utilized.
Record Keeping Requirements
The ATO requires you to keep records showing:
- Date of acquisition and disposal
- Amount received on disposal
- Cost base calculations
- How and when you applied losses to gains
- Any carried forward losses from previous years
Good portfolio tracking software maintains these records automatically, ensuring you never miss a legitimate loss offset opportunity.