Tax loss harvesting often fails because the math doesn't work for most people
Tax loss harvesting sounds straightforward: sell an investment at a loss, use that loss to offset gains or income, and reduce your tax bill. In practice, it rarely saves money for the average investor. The reason is simple math. To benefit, you need enough losses to offset real gains, you need to be in a tax bracket where the offset actually matters, and you need to hold investments long enough that the strategy's costs don't eat the savings.
Most people who attempt tax loss harvesting end up spending more on trading costs, advisory fees, or account management than they save in taxes. The strategy works only in narrow situations: you have substantial investment gains in a single year, you are in a high tax bracket, and you can execute the trades yourself without paying someone else to do it.
Key Takeaways
- Tax loss harvesting requires you to have investment gains in the same year you take losses, which most people do not have in most years.
- If you pay an advisor or robo-advisor to harvest losses for you, their fees typically exceed the tax savings by the time you account for trading costs.
- The wash-sale rule prevents you from buying back a substantially identical investment for 30 days, which often forces you into a worse replacement investment.
- Losses carried forward to future years lose value because you cannot use them until you have gains, and tax rates may change by then.
- For most people with modest investment accounts, the tax savings are too small to justify the complexity and cost.
The fee problem: what the strategy costs versus what it saves
A robo-advisor or financial advisor who harvests losses for you typically charges between 0.25% and 1% of assets under management annually. On a $100,000 account, that is $250 to $1,000 per year in fees alone. Trading costs, even at brokers with no commission, include bid-ask spreads and market impact. Over a year, these costs often total 0.1% to 0.3% of the account value.
To break even, your tax savings must exceed these costs. A tax loss of $10,000 saves you money only if your tax bracket is high enough. In a 24% federal tax bracket, a $10,000 loss saves $2,400. But if you paid $500 in fees and $300 in trading costs to harvest that loss, your net savings drop to $1,600. For someone in a 12% bracket, the same $10,000 loss saves only $1,200 before fees—and you are now underwater.
The math works only if you do the harvesting yourself, have substantial gains to offset, and are in a high tax bracket (32% or higher federally). For everyone else, the costs exceed the benefit.
You need gains in the same year to use the losses
Tax loss harvesting only reduces your tax bill if you have capital gains or ordinary income to offset in the same tax year. Most people do not. If you have a $10,000 loss but no gains that year, you can carry the loss forward to future years—but only $3,000 of it can offset ordinary income each year. The remaining $7,000 sits unused until you have gains.
This creates a timing problem. You harvest a loss today hoping to use it next year, but next year you may have no gains. The loss sits on your books for years. Meanwhile, tax rates may change. If tax rates drop by the time you use the loss, the tax savings shrink. If you move to a lower-income state or retire into a lower bracket, the loss becomes nearly worthless.
For the strategy to work, you need to know in advance that you will have gains this year or next. Most investors do not plan their portfolio that precisely.
The wash-sale rule forces you into worse replacement investments
When you sell an investment at a loss, the IRS wash-sale rule prevents you from buying back that same investment or a substantially identical one for 30 days. This rule exists to prevent people from harvesting losses while keeping the same exposure.
In practice, it forces you to buy a different investment for 30 days. If you sold a total stock market index fund at a loss, you might buy a different index fund (say, one tracking a slightly different market segment) to stay invested. But that replacement fund may perform differently. If the market rises 2% in those 30 days and your replacement fund only rises 1%, you have lost money on the replacement trade. By the time you switch back after 30 days, your tax savings may be gone.
This is especially painful in volatile markets. You harvest a loss to reduce taxes, but the replacement investment underperforms, and you end up worse off than if you had done nothing.
Losses carried forward lose value over time
When you cannot use a loss in the current year, it rolls forward to the next year. But a loss is worth less in the future than today because of inflation and opportunity cost. A $10,000 loss today is worth $2,400 in taxes (at 24% rate). That same loss next year is worth $2,400 in nominal dollars, but inflation has reduced its real value. If inflation is 3%, the loss is worth about $2,328 in today's dollars.
More importantly, you do not know what your tax situation will be in future years. You might retire and drop into a 12% bracket, cutting the loss's value in half. You might move to a state with no income tax. You might have no gains for years and never use the loss at all. The longer a loss sits unused, the less certain its value becomes.
The strategy assumes you will stay invested in the same asset class
Tax loss harvesting assumes you want to stay invested in the same type of asset after you harvest the loss. If you sell a stock fund at a loss and buy a bond fund instead, you have changed your investment strategy to avoid the wash-sale rule. That change may hurt your long-term returns more than the tax savings help.
Similarly, if you harvest losses in a down market and then the market recovers, you have locked in a loss while missing the recovery. You harvested a loss on a fund that was down 15%, replaced it with something else, and then watched the original fund rise 20%. The tax savings do not compensate for the opportunity cost.
Small accounts make the strategy pointless
For accounts under $50,000, tax loss harvesting rarely makes financial sense. The potential tax savings are too small to justify the complexity. A $50,000 account with a $5,000 loss saves $1,200 in taxes (at 24% rate). After paying an advisor 0.5% to manage the harvest, you have paid $250 in fees. Your net savings is $950—which is real money, but not enough to justify ongoing complexity or the risk of wash-sale mistakes.
For accounts under $100,000, the math only works if you do it yourself and you have substantial gains to offset. For accounts under $50,000, it almost never works.
Frequently Asked Questions
Does tax loss harvesting work if I do it myself without paying an advisor?
It works better, but only if you have gains to offset and you are in a high tax bracket (32% or higher). You still face the wash-sale rule and the risk of buying a worse replacement investment. If your account is under $100,000, the tax savings are usually too small to justify the effort and risk.
What if I harvest losses every year—doesn't that add up?
Only if you have gains every year to offset them. Most investors do not. If you harvest losses in years with no gains, those losses sit unused and lose value over time. The cumulative benefit is usually smaller than the cumulative cost of trading and management.
Can I use losses to offset my regular income, not just investment gains?
Yes, but only $3,000 per year. The rest carries forward. This means a large loss takes years to use up, and its value declines over time due to inflation and changing tax rates. For most people, this makes the strategy even less attractive.
What happens if I harvest a loss and then the investment rises before I can buy it back?
You have locked in a loss and missed the recovery. This is the opportunity cost of the strategy. If the investment rises 10% before you can buy back a replacement, the tax savings may not cover that loss. This risk is highest in volatile markets, which is exactly when losses are easiest to harvest.
Is tax loss harvesting worth it for someone with a $200,000 account?
Only if you have substantial gains in the same year, you are in a high tax bracket, and you do the harvesting yourself. If you pay an advisor to do it, the fees eat most of the benefit. If you do not have gains to offset, the losses sit unused and lose value. Even at $200,000, the strategy works for only a small fraction of investors in specific situations.