Tax-loss harvesting means deliberately selling a position at a loss to offset realised gains elsewhere. Whether a holder can sell at a loss and immediately buy back the same asset depends entirely on jurisdiction: as the rules stand today, the US wash-sale rule does not apply to crypto, while the UK has a 30-day analogue that does.
What harvesting actually does
Harvesting is the deliberate realisation of a loss to reduce a tax bill. A holder sitting on a realised gain from earlier in the year can sell a separate position that is underwater, crystallising a capital loss that offsets the gain. The portfolio's overall market exposure need not change much — the point is to convert an unrealised loss into a realised one while it is useful.
The mechanics depend on two things: whether the jurisdiction allows an immediate repurchase of the same asset, and which specific lots the disposal consumes. Both require lot-level records to do correctly, because a harvested loss is only as good as the basis figure it is measured against.
The United States: no wash-sale rule for crypto, as the rules stand today
The US wash-sale rule, in IRC section 1091, disallows a loss when a taxpayer sells a security at a loss and buys a substantially identical one within 30 days before or after the sale. The rule is written to apply to stock or securities.
Crypto is currently classified as property for US federal tax purposes, not as stock or securities. As a result, the wash-sale rule does not currently apply to crypto in the US. A holder can sell a token at a loss, realise that loss for offset purposes, and repurchase the same token immediately afterwards without the loss being disallowed.
This is a genuine planning advantage that does not exist for equities — but it is a legislative grey area, not a settled principle. Proposed bills have repeatedly targeted exactly this gap, and the treatment could change. The correct framing is always as the rules stand today, and the correct posture is to confirm the current position with a professional before relying on it for a material amount.
The United Kingdom: a 30-day analogue that does apply
The UK has no separate "wash-sale rule" by that name, but its section-104 pooling rules contain an effective analogue that achieves much the same thing for crypto.
Two matching rules sit on top of the pool:
- The same-day rule. Disposals are matched first against acquisitions of the same asset on the same day.
- The 30-day rule (often called "bed and breakfasting"). A disposal is then matched against any acquisitions of the same asset in the following 30 days, before it is matched against the section-104 pool.
The combined effect is that a UK holder who sells at a loss and rebuys the same asset within 30 days does not get to set that loss against the general pool — the disposal is matched against the rebuy instead, neutralising the harvest. To realise a loss in the UK, the holder generally has to stay out of the asset for more than 30 days, accepting the market exposure that creates.
HIFO and year-end timing
In jurisdictions that permit specific identification, the choice of lot matters as much as the timing.
HIFO — disposing of the highest-basis lots first — maximises the loss harvested, because it sells the lots with the largest difference between basis and current price. A holder harvesting losses under FIFO might realise a small loss or even a gain on old low-basis lots; the same disposal under HIFO targets the expensive recent lots and books the largest available loss.
Timing relative to the tax-year boundary is the other lever. A loss is only useful in a year where there is a gain to offset, or where loss carry-forward rules make it worth banking. Harvesting decisions therefore cluster around the year-end, and a holder needs to know — before the boundary — which lots are underwater, by how much, and what the realised effect of selling each would be.
All of this rests on lot-level records. Without them, a holder cannot see which lots are underwater, cannot select the highest-basis lots, and cannot prove the loss was real if asked. Lot-level records are the prerequisite for harvesting correctly, in any jurisdiction.
How HQ Wealth supports the decision
HQ Wealth holds every acquisition as its own CostBasisLot, so a holder can see the basis and current unrealised position of each lot before placing a harvest trade and model the realised effect of disposing of a specific lot. Because the cost-basis method is locked at portfolio creation, the disposal draws lots down consistently — and a holder running HIFO sees the highest-basis lots selected automatically to maximise the harvested loss.
For UK holders the section-104 pool model applies the same-day and 30-day matching rules directly, so a rebuy inside the window is matched against the disposal as HMRC requires, rather than being mistaken for a clean harvest. The tool shows what the rules actually produce; the decision of when to harvest, and confirmation of the current wash-sale position, belongs with the holder and a professional in their jurisdiction.
Takeaway: As the rules stand today, US holders can harvest crypto losses and rebuy immediately because the wash-sale rule does not reach property, while UK holders are caught by the same-day and 30-day pool rules. Either way, HIFO and year-end timing only work if every lot's basis is on record.