Losing money on an investment is bad. Losing money and not using it to cut your tax bill is worse.
In Ireland, a capital loss is worth up to 33 cents for every euro, because it reduces the gains you'd otherwise be taxed on. Here's how it works.
Same year first
Add up everything you sold in the year. Gains go on one side, losses on the other. Net them off.
Example
Sold Apple shares: gain €5,000.
Sold a crypto coin: loss €2,000.
Net gain: €3,000.
Less €1,270 exemption: €1,730 taxable. Tax: €570.90.
Without the loss you'd pay €1,230.90. The loss saved you €660.
You don't get to choose whether to use a same-year loss. It comes off your gains automatically, even if that means you don't use all of your €1,270 exemption.
Carrying losses forward
If your losses are bigger than your gains, the leftover carries forward to next year. And the year after. There's no expiry.
Next time you have a gain, the old loss comes off it. Then your €1,270 exemption applies to whatever's left.
Example
2025: loss of €4,000, no gains. €4,000 carried forward.
2026: gain of €3,000. Use €3,000 of the old loss. Tax: €0.
€1,000 still carried forward to 2027.
One catch: you can't carry losses back. A loss this year won't get you a refund on last year's tax.
Claim it or lose it
A loss only counts if you tell Revenue about it. If you made losses and no gains, it's tempting not to file. File anyway. That return is your record, and it's what lets you use the loss later.
Rules that catch people out
- Selling and buying back within 4 weeks. If you sell shares at a loss and buy the same shares back within four weeks, that loss can only be used against a later gain on those same shares. People call this bed and breakfasting.
- Losses on Irish and EU ETFs. Funds taxed under exit tax (41%) are a separate system. A loss on one generally can't be used against your ordinary 33% gains.
- Selling to family. A loss on a sale to a connected person, like a relative, can usually only be used against gains from sales to that same person.
- Married couples. If you're taxed jointly, one spouse's losses can usually be used against the other's gains. Each of you still has your own €1,270.
Short version
- Same-year losses come off gains first.
- Leftover losses carry forward forever.
- No carrying back.
- File your return so the loss is on record.
- Watch the 4-week buy-back rule.