Tax-loss harvesting is one of the most talked-about tools in wealth management and one of the most misunderstood. Done well, it can make a taxable portfolio meaningfully more tax-efficient. Done carelessly, it can produce disallowed losses, unwanted changes to your portfolio, or simply a smaller tax bill now and a larger one later. Here is what it does, and what it does not.
In brief
- Harvesting realizes a loss to offset gains, and up to $3,000 a year of ordinary income.
- It usually defers tax by lowering your cost basis. It does not eliminate it, with a few exceptions.
- The wash sale rule disallows a loss if you buy the same or substantially identical security within 30 days.
- Harvesting works best as a year-round process, not a December scramble.
How it works
When an investment in a taxable account is worth less than you paid, you can sell it, realize the loss, and immediately reinvest in something similar but not substantially identical so your market exposure stays roughly the same. The realized loss offsets capital gains this year. Losses above your gains can offset up to $3,000 of ordinary income, and anything left carries forward indefinitely.
Why it is usually a deferral
The replacement investment has a lower cost basis, so when you eventually sell it, the gain is larger. The benefit comes from paying later rather than now, from turning short-term gains into long-term ones, and in some cases from never paying at all: assets held until death generally receive a step-up in basis, and appreciated shares given to charity avoid the gain.
The wash sale rule
If you buy the same or a substantially identical security within 30 days before or after the sale, the loss is disallowed and added to the basis of the new shares. This applies across your accounts, including IRAs and a spouse's accounts, and reinvested dividends can trigger it. Automated dividend reinvestment is a common accidental culprit.
Where it adds the most value
- When you have large gains to offset, such as from a concentrated stock sale, a business sale, or a fund distribution.
- In volatile markets, when individual positions dip even if the overall market is up.
- In direct indexing portfolios, which hold individual stocks and therefore offer many more harvesting opportunities than a single fund.
- In bond portfolios after rates rise, when older bonds trade below cost.
Where to be careful
- Do not let the tax tail wag the dog. The replacement must still fit your plan.
- Watch trading costs and bid-ask spreads on less liquid holdings.
- Track carryforwards and coordinate with your CPA so harvested losses are used well.
Published October 30, 2026. Based on federal tax law in effect as of that date. Tax law can change, including retroactively.
This newsletter is for general educational purposes only. It is not a recommendation of any security, fund, or strategy, and it is not tax or legal advice. Tax-loss harvesting does not guarantee a better after-tax result, and the benefit depends on your circumstances. Viva Wealth Management and Cross Financial Advisors, LLC do not provide tax or legal advice. Consult your own CPA and attorney about your situation. All investing involves risk, including the loss of principal.