Why tax-loss harvesting matters
It may improve after-tax return, but benefits depend on jurisdiction, investor, future gains, rates, timing, and transaction costs.
How it is applied
Investors identify eligible losses, lots, offset rules, replacement exposure, wash-sale or equivalent restrictions, costs, and tracking impact. Tax-loss harvesting realizes selected investment losses to offset gains or, where permitted, other taxable income while maintaining an appropriate portfolio. The process identifies tax lots, applicable matching or wash-sale rules, replacement exposure, transaction costs, holding periods, carryforwards, and the investor’s current and expected future tax rates.
Portfolio example
An investor sells one index fund at a loss and buys a sufficiently different replacement, subject to local rules. An investor realizes a 10,000 loss in one equity fund and buys a different broad-market fund to maintain exposure. The loss offsets a 10,000 realized gain, but the replacement must satisfy applicable rules. The new holding has its own cost basis and future tax consequence.
How to interpret it
The benefit is often tax deferral rather than permanent savings. Investment merit should not be sacrificed solely for tax. The strategy usually defers tax rather than permanently eliminating it because the replacement asset begins with a new basis. Deferral can improve compounding, and permanent benefit may arise when future rates fall or assets receive different basis treatment, subject to local law.
Limitations and common misconceptions
Rules vary and related accounts or derivatives can trigger restrictions. Spreads, market movement, and future tax rates can erase benefit. Rules vary by jurisdiction and account. Similar replacement securities can invalidate the loss, while waiting can create market exposure gaps. Spreads, taxes, tracking difference, and portfolio drift can exceed benefits. Harvesting losses solely for tax can undermine investment quality or increase future gains. A glossary page should remain general, state that individualized tax advice is required, and date any jurisdiction-specific references. It should connect tax lots, cost basis, realized gain, capital gain, and wash-sale concepts. Examples must include future basis rather than present the tax saving as free return. Portfolio-wide optimization should avoid harvesting one loss while creating a larger unintended factor, sector, or duration change. Benefits depend on when the saved tax is eventually paid and what return the deferred amount earns. Recordkeeping must link the original and replacement trades so future basis, holding period, and rule compliance can be verified.
Sources and further reading
- Publication 550: Investment Income and ExpensesU.S. Internal Revenue Service
- Dividends and Other Corporate DistributionsU.S. Internal Revenue Service