Concentrated Company Stock: Here's What a 30% Drop Could Actually Do to Your Net Worth

Q: Q: How much company stock is too much to hold?

A: There's no universal number, but many fiduciary advisors recommend keeping any single stock position under 10–15% of total net worth once shares have vested and taxes have been considered. The right threshold depends on your age, other assets, income stability, and risk tolerance, and other circumstances.

Q: Q: Isn't it better to hold and avoid paying capital gains tax?

A: Taxes matter and can be a drag on returns, but they're not the only factor. The expected cost of a concentration-driven decline modeled across realistic market scenarios is often larger than the tax bill from selling and diversifying, especially when sales are spread across multiple tax years, or paired with tax-loss harvesting and other tax saving opportunties elsewhere in the portfolio.

Q: Q: What is a 10b5-1 plan and do I need one?

A: A 10b5-1 plan is a pre-scheduled, pre-arranged trading plan that lets employees and insiders sell company stock on a set schedule established when they don't possess material nonpublic information. It's most relevant for executives, insiders, or anyone subject to trading windows or blackout periods, though the discipline it enforces can be useful for any concentrated holder.

Q: Q: Does this apply to RSUs, ISOs, NSOs, and ESPP shares equally?

A: The concentration risk itself is the same regardless of the type of equity compensation, but the tax treatment for each type differs meaningfully. RSU's are taxed as they vest and when they are sold.ISOs carry AMT considerations.NSOs are taxed as ordinary income at exercise.ESPP shares have qualifying versus disqualifying disposition rules. A diversification plan should be built around the specific tax character of each holding, not treated as one uniform pool.

Q: Q: When should I talk to an advisor about a concentrated position?

A: As soon as a single stock position exceeds roughly 10% of your net worth, it's worth having a plan. even if the plan is simply to monitor it and diversify gradually. Waiting until after a significant decline eliminates most of the proactive strategies that could have reduced the impact.

Vince DeCrow, CFP®
Aug 14
5 min read

A 30% drop in a single stock that makes up 40% of your net worth would cut your total net worth by roughly 12% before accounting for the taxes you'd owe if you'd sold to diversify, or the compounding effect on retirement timelines. The more concentrated the position, the more a single company's bad quarter becomes a personal financial event, not just a market event.

Why Concentrated Stock Feels Safe Until It Isn't

Employees who receive RSUs, ISOs, NSOs, or ESPP shares often end up with a large share of their net worth tied to one company, which also happens to be the company that pays their salary. It may not feel risky day-to-day because the stock is familiar, the paycheck is stable, and the shares often show a large unrealized gain. That gain is exactly what makes the position dangerous: it's a period of returns that is often perceived as something that's inevitably going to continue on forever.

Concentration risk is different from market risk. A diversified portfolio can absorb a bad sector or a bad year. Whereas, a concentrated position ties your home down payment, your retirement date, and your children's tuition to the fortunes of one company's revenue growth, earnings calls, leadership decisions, governance, and competitive position. While your specific role in the company (such as a sales role) may allow you to influence the company's fortunes (such as driving revenue growth), most of these variables are not within your control.

What Does a 30% Drop Actually Cost You?

The math is straightforward, but most people ignore running it. Below is what a 30% decline looks like at different levels of concentration, assuming a $1,000,000 total net worth.

What a 30% Drop of a Concentrated Stock Position Actually Costs You

These figures only capture the direct loss. They don't include the opportunity cost of not diversifying earlier, the tax bill that made you hesitate to sell, or the fact that something severe enough to cause a company to drop 30% may also lead to the company handing out layoffs.

The Double Jeopardy Problem

For most concentrated stock holders, the position and the paycheck come from the same source. A 30% stock decline often correlates with company-specific bad news, like missed earnings, problematic restructuring, leadership turnover, or a weak product cycle. Those same conditions are the ones most likely to produce layoffs or hiring freezes.

That means the scenario where your portfolio takes the biggest hit is often the same scenario where your income is least secure. Diversifying isn't about doubting your employer or your ability to help drive company growth. Rather, it's about not letting one company control both sides of your financial life at the same time.

What to Do About It: Core Strategies

1. Set a concentration threshold before you need one

Many advisors use 10%–15% of net worth in a single stock as a general rule of thumb ceiling, adjusted for the person's age, other assets, risk tolerance, and any other unique circumstances. Deciding on a threshold in advance rather than reacting after a drop can help to remove emotion from the decision.

2. Manage the tax bill, don't let it drive the decision

Unrealized gains create a real incentive to hold appreciated stock, but the tax cost of diversifying is usually smaller than the risk of a 30% or greater decline in a concentrated position. Strategies like tax-loss harvesting elsewhere in the portfolio, gifting appreciated shares to donor-advised funds, or spreading sales across multiple tax years can reduce the bill without eliminating the diversification.

3. Consider exchange fund strategies

For very large, low-basis positions, exchange funds can reduce downside exposure without triggering an immediate taxable sale. These strategies carry their own costs and complexity, and they are typically appropriate only above certain position sizes.

4. Reinvest proceeds with a plan, not a pause

Selling concentrated stock without a reinvestment plan often leaves the proceeds sitting in cash indefinitely. Coordinating the sale with an already-built target allocation keeps the money working rather than sitting on the sidelines out of decision fatigue.

A Real-World Example

Consider an employee at a mid-cap technology company with $800,000 in vested RSUs and ESPP shares, representing 55% of their $1.45 million net worth. A 30% drop in the stock, which is not an unusual single-year move for a mid-cap tech name, would reduce their net worth by roughly $240,000, or about 16.5%, in addition to any decline elsewhere in the portfolio. Whereas, a diversification plan to gradually reduce the position to 15% of net worth over time with tax-aware lot selection would limit that same 30% stock decline to a roughly 4.5% hit to total net worth.

Frequently Asked Questions

How much company stock is too much to hold?

There's no universal number, but many fiduciary advisors recommend keeping any single stock position under 10–15% of total net worth once shares have vested and taxes have been considered. The right threshold depends on your age, other assets, income stability, and risk tolerance, and other circumstances.

Isn't it better to hold and avoid paying capital gains tax?

Taxes matter and can be a drag on returns, but they're not the only factor. The expected cost of a concentration-driven decline modeled across realistic market scenarios is often larger than the tax bill from selling and diversifying, especially when sales are spread across multiple tax years, or paired with tax-loss harvesting and other tax saving opportunties elsewhere in the portfolio.

What is a 10b5-1 plan and do I need one?

A 10b5-1 plan is a pre-scheduled, pre-arranged trading plan that lets employees and insiders sell company stock on a set schedule established when they don't possess material nonpublic information. It's most relevant for executives, insiders, or anyone subject to trading windows or blackout periods, though the discipline it enforces can be useful for any concentrated holder.

Does this apply to RSUs, ISOs, NSOs, and ESPP shares equally?

The concentration risk itself is the same regardless of the type of equity compensation, but the tax treatment for each type differs meaningfully.

RSU's are taxed as they vest and when they are sold.
ISOs carry AMT considerations.
NSOs are taxed as ordinary income at exercise.
ESPP shares have qualifying versus disqualifying disposition rules. A diversification plan should be built around the specific tax character of each holding, not treated as one uniform pool.

When should I talk to an advisor about a concentrated position?

As soon as a single stock position exceeds roughly 10% of your net worth, it's worth having a plan. even if the plan is simply to monitor it and diversify gradually. Waiting until after a significant decline eliminates most of the proactive strategies that could have reduced the impact.

Disclosure

RISE Investment Management, LLC ("RISE" or "RISE Investments") is an investment adviser registered under the Investment Advisers Act of 1940. Registration of an investment adviser does not imply any level of skill or training. This publication is solely for informational purposes and past performance is not indicative of future results. Any description of products, services, and performance results of RISE contained in this publication are not an offering or a solicitation of any kind. No advice may be rendered by RISE Investments unless a client service agreement is in place. Advisory services are only offered to clients or prospective clients where RISE Investments and its representatives are properly licensed or exempt from licensure. All of the information in this publication is believed to be accurate and correct as the date set forth. RISE does not have or accept responsibility or an obligation to update such information. Please note, this article is for education purposes and should not be treated as tax or legal advice. This article is not a substitute for legal or tax advice from your professional legal or tax advisor.