Tax-Loss Harvesting

Tax-loss harvesting is the practice of deliberately selling an investment that's currently at a loss in order to realize (or "book") that loss for tax purposes, which can then be used to offset capital gains realized elsewhere in the same portfolio, reducing overall tax liability for the year.

The mechanism works because tax rules generally allow capital losses to be set off against capital gains of the same type — short-term losses against short-term gains, and (in most cases) long-term losses against long-term gains, with specific rules varying by jurisdiction and periodically updated regulations. An investor holding both a profitable stock they're ready to sell and a separate losing position they no longer believe in can sell both in the same financial year, using the loss to reduce the tax owed on the gain.

A useful, common scenario: an investor rebalancing a portfolio (as covered in the earlier asset allocation topic) who needs to trim an overweight equity position that's up significantly, and who also happens to be holding a smaller position that hasn't performed as expected, can often execute both trades together — the loss on one position offsetting some of the tax owed on the gain from the other — accomplishing a planned portfolio adjustment somewhat more tax-efficiently than executing the sales in isolation.

An important caution: tax-loss harvesting should follow investment logic, not the other way around. Selling a fundamentally sound investment purely to harvest a tax loss, only to buy back something similar shortly after, can run into specific tax rules in various jurisdictions designed to prevent exactly this kind of artificial loss-booking, and more importantly, it risks missing a genuine recovery in an investment you actually still believe in. Tax-loss harvesting works best as a secondary consideration layered onto decisions you'd be making anyway for portfolio or fundamental reasons, not as the primary driver of what to buy or sell.