By Chris DeWolfe
Senior Financial Advisor at Investment Consulting Group

Published October 21st, 2026

Should You Sell an Investment With a Large Unrealized Gain? Understanding the Tax Trade-Off

For many investors, one of the hardest decisions in a taxable investment account is knowing when to sell an investment that has appreciated significantly.

The investment may have performed extremely well. Perhaps you've owned it for 10, 15, or even 20 years. But now the position has become a large part of your portfolio, and selling it could create a substantial capital-gains tax liability.

That can lead to a familiar thought:

"I don't want to sell because I don't want to pay the taxes."

It's an understandable reaction.

But taxes are only one part of the decision. When a taxable investment has a large unrealized gain—or when one stock has become a concentrated position—it can be helpful to step back and evaluate the investment based on its current value, current risk, and current role in the portfolio, rather than simply its historical performance.

What Is an Unrealized Gain?

An unrealized gain occurs when an investment is worth more today than its original cost basis, but the investment has not been sold.

For example, suppose you purchased $200,000 of an investment years ago and it is now worth $600,000.

You have a:

• $200,000 cost basis
• $400,000 unrealized gain
• $600,000 current market value

The gain remains "unrealized" until you sell the investment.

If you sell, some or all of the gain may become taxable, depending on the circumstances.

This is where the investment decision can become complicated.

Why Do Investors Hesitate to Sell Appreciated Investments?

Taxes can create what is sometimes called tax paralysis—the reluctance to make a portfolio change because realizing a gain creates an immediate tax liability.

An investor may know that an investment has become too large or no longer fits their objectives, but the potential tax bill makes selling feel painful.

There is also an emotional component.

If an investment has performed exceptionally well, selling it can feel like giving up on a winner.

And if the investor has held it for many years, the original purchase price can become psychologically important.

But the original purchase price is not necessarily the most relevant question today.

The "If You Had the Cash Today" Test

One way to think about a large appreciated position is to ignore the historical purchase for a moment.

Ask yourself:

If I had the current market value of this investment in cash today, would I invest all of that money back into the same investment?

If the answer is yes, continuing to hold may be reasonable.

But if the answer is no, it may be worth examining why.

Perhaps the position has become too large relative to the rest of the portfolio.

Perhaps the investment carries more risk than you are comfortable with today.

Perhaps your financial goals have changed.

Perhaps you are approaching retirement and your portfolio needs to provide a different balance of growth, income, liquidity, and diversification.

The tax liability is still important. But it is only one part of the decision.

What Is a Concentrated Investment Position?

A concentrated position occurs when a single investment represents a significant portion of an investor's portfolio or overall wealth.

There is no single percentage that defines "concentrated" for every investor. The appropriate level depends on factors such as the investor's financial resources, goals, risk tolerance, other assets, income, and the characteristics of the investment.

Concentration can happen in several ways.

For example:

• An employee accumulates shares of their employer over many years.
• Stock compensation grows substantially.
• An investor holds a single company for decades.
• An inherited stock position appreciates significantly.
• A long-term investment becomes a much larger percentage of the portfolio simply because it outperformed the other holdings.

The challenge is that the investment may have become concentrated because it performed well.

That can make the decision to diversify especially difficult.

Is It Better to Hold an Investment and Avoid the Tax?

Not necessarily.

Avoiding a tax bill isn't the same as maximizing financial outcomes.

Suppose an investor owns $1 million of a single stock and has a $700,000 unrealized gain.

Selling the position could create a significant tax liability.

But continuing to hold the entire $1 million also means continuing to accept the investment risk associated with having that much wealth tied to one company.

The investor is effectively choosing between two costs:

The potential tax cost of diversifying

and

The potential investment risk of remaining concentrated.

There isn't a universal answer to which choice is better.

The decision depends on the investor's circumstances, tax situation, financial goals, risk tolerance, and time horizon.

That's why the question shouldn't simply be:

"How much tax will I owe if I sell?"

It should be:

"Is the potential tax cost of reducing this position justified by the potential benefits of diversification?"

What About an Investment That Has Performed Extremely Well?

A common psychological trap is to think:

"This investment has done so well. I don't want to sell it now."

But past performance doesn't determine what an investment will do in the future.

A position that has grown from $100,000 to $1 million has already produced a substantial return.

The decision going forward should be based on the investment's current value and future prospects, not simply the fact that it has performed well historically.

The same principle applies in reverse.

An investment that has appreciated substantially isn't necessarily something you should sell simply because it has a large gain.

The important question is whether the investment still makes sense today, given your overall portfolio and financial objectives.

How Can You Diversify a Large Appreciated Position?

Selling an entire position at once is not the only possible approach.

Depending on the circumstances, investors may consider a gradual transition.

For example, an investor might:

• Sell a portion of the position each year
• Prioritize shares with different cost bases
• Use investment losses to offset realized gains when appropriate
• Coordinate gain realization with their broader tax situation
• Reinvest proceeds into a more diversified portfolio
• Evaluate charitable giving strategies when appropriate
• Use other tax-aware investment strategies during the transition

The appropriate strategy depends heavily on the investor's circumstances.

The important point is that portfolio diversification and tax management don't necessarily have to be an all-or-nothing decision.

What Is Tax-Aware Portfolio Transition Analysis?

When an investor has substantial unrealized gains, it can be useful to model different transition scenarios before making changes.

This is sometimes referred to as tax-aware portfolio transition analysis.

Rather than simply asking:

"What should I sell?"

the analysis can consider questions such as:

• Which positions have the largest gains?
• What are the cost bases?
• How much tax might be generated under different scenarios?
• Could losses offset some of the gains?
• How quickly should the portfolio be diversified?
• What would happen if gains were realized over multiple years?
• How would the portfolio's risk change?
• What investments would replace the positions being sold?
• What could the portfolio look like after the transition?

This allows an investor to compare potential paths forward rather than making a decision based solely on the size of the tax bill.

A Simple Hypothetical Example

Consider an investor with a $1 million taxable portfolio.

Suppose:

• $600,000 is invested in one company
• The cost basis of that position is $150,000
• The position therefore has $450,000 of unrealized gain
• The remaining $400,000 is diversified across other investments

The investor recognizes that having 60% of the taxable portfolio in one company creates concentration risk.

However, selling the entire $600,000 position could generate a significant taxable gain.

One possible approach would be to do nothing.

Another would be to sell the entire position immediately.

A third approach could involve developing a multi-year transition strategy designed to gradually reduce the concentration while considering the tax consequences of each step.

The point isn't that the third approach is always the right answer.

The point is that there are often more choices than simply "sell everything" or "do nothing."

What Role Does Cost Basis Play?

Cost basis is particularly important when evaluating appreciated investments.

Two investors can own the same investment at the same market value but have very different tax situations.

For example:

Investor A

• Current value: $500,000
• Cost basis: $450,000
• Unrealized gain: $50,000

Investor B

• Current value: $500,000
• Cost basis: $100,000
• Unrealized gain: $400,000

Both investors own $500,000 of the same investment.

But the potential tax consequences of selling are very different.

That's why tax-aware investment management requires more than simply looking at the current market value of a portfolio.

Cost basis matters.

What About Direct Indexing?

For some investors, direct indexing or personalized indexing may be another tool worth considering when managing a taxable portfolio.

Rather than owning an index through a mutual fund or ETF, direct indexing generally involves owning individual securities designed to track or represent an index.

Because the investor owns individual securities, there may be opportunities to realize losses in individual holdings while maintaining a desired level of market exposure.

This can potentially create additional tax-management opportunities.

However, direct indexing isn't appropriate for every investor. Account size, investment objectives, costs, tax circumstances, portfolio complexity, and other factors all matter.

It should be considered as one potential component of a broader investment strategy—not as a solution simply because an investor has a tax problem.

When Does Paying the Tax Make Sense?

This is perhaps the most important question.

Sometimes the answer is yes.

If selling an appreciated investment reduces significant concentration risk, improves diversification, better aligns the portfolio with your financial goals, or allows you to pursue a more appropriate investment strategy, the tax cost may be worthwhile.

The objective isn't to avoid every tax bill.

It is to make thoughtful decisions about whether the benefit of changing the portfolio justifies the associated tax cost.

In other words:

A tax bill is a cost. But so is taking more investment risk than you need to.

Good tax-aware investing considers both.

The Bottom Line

Large unrealized gains can make investment decisions more complicated—but they don't necessarily mean an investor is stuck.

The decision to sell an appreciated investment should consider more than the potential tax bill.

It should also consider:

• Portfolio concentration
• Investment risk
• Diversification
• Cost basis
• Financial goals
• Time horizon
• Current and future tax circumstances
• The potential after-tax outcome

For investors with substantial appreciated assets, a tax-aware transition analysis can help evaluate different ways to move toward a more diversified or tax-efficient portfolio without treating the decision as an all-or-nothing choice.

At ICG, we believe the question isn't simply "How can I avoid paying taxes?"

The better question is:

"How can I make the best overall financial decision while understanding the tax consequences?"

That perspective can help investors make more informed decisions about appreciated investments, concentrated positions, and the taxable portfolios they rely on to support their financial goals.

This article is provided for educational and informational purposes only and is not intended to provide individualized investment, tax, or legal advice. Tax laws and regulations are subject to change. Individual circumstances vary, and investors should consult their qualified tax, legal, and financial professionals regarding their specific situation.