Why “Just Diversify” Can Be Bad Advice When One Stock Made You Rich

Diversification is one of the most repeated ideas in investing, and for good reason. For most people, it is sound advice. Spread risk. Own many assets. Avoid letting one company dictate your financial future.

But for people who became wealthy because one stock multiplied far beyond expectation, the usual advice can become too simplistic to be useful.

That is especially true when the concentrated position is not a speculative mistake but the very reason the investor is now wealthy in the first place. Telling someone with tens of millions in a single high-performing stock to “just diversify” sounds prudent. It can also be financially clumsy, tax-inefficient and emotionally disconnected from the reality of how concentrated wealth actually behaves.

The more useful question is rarely whether full diversification is theoretically better. Of course, in abstract portfolio terms, it usually is. The more relevant question is: how much diversification is actually required to make the rest of life financially secure?

That is a very different exercise.

For someone with a very large position in Nvidia or any other runaway winner, the risk is obvious. A single stock can create extraordinary wealth, but it can also create extraordinary dependence. The portfolio may look enormous, yet still feel fragile because so much of the future depends on one ticker. This is the strange psychology of concentrated wealth. On paper, the investor may be financially independent. In practice, the investor may still feel locked into one company’s fate.

This is why total diversification is not always the first or best move. Selling everything at once can trigger a massive tax bill, destroy optionality and force a cleaner portfolio at the cost of an inefficient one. In many cases, the smarter goal is not to eliminate concentration entirely, but to reduce it enough that the household’s essential future no longer depends on the concentrated asset continuing to perform.

That is the key distinction. A household may not need to diversify all $15 million of a concentrated holding if, for example, $4 million of diversified assets is already enough to fund the desired lifestyle. At that point, diversification becomes less about obeying a portfolio rule and more about building a floor under life itself. Once the floor is secure, the remaining concentrated position can still exist as upside rather than as existential risk.

This is what people often miss about diversification: it is not a moral virtue. It is a tool. And like any tool, it should be used in proportion to the problem being solved.

For a high-net-worth employee or founder with a massive stock position, the first planning task is to identify the amount of diversified capital required to support long-term spending, not to chase some arbitrary target percentage in any single security. If the household needs $200,000 of annual spending support and can reasonably withdraw that from a diversified portfolio, then the planning priority is to secure that portfolio. Everything after that is a secondary question.

Once the objective is framed that way, the strategy becomes more nuanced.

Some diversification can happen through new savings rather than immediate selling. Maxing out workplace retirement plans, using the mega backdoor Roth, and building out pre-tax and Roth balances in diversified assets all help reduce overall concentration without forcing a major taxable event in the brokerage account. In that sense, diversification does not always begin with what you sell. Sometimes it begins with what you stop adding to and what you deliberately build around it.

Tax management then becomes central. This is where concentrated stock planning differs most from ordinary portfolio advice. A large embedded gain makes every diversification decision partly a tax decision. That means loss harvesting, careful sequencing of sales, exchange funds, covered-call strategies, charitable gifting and donor-advised funds can all become relevant. The investor is no longer simply rebalancing. The investor is trying to preserve optionality while reducing risk and avoiding avoidable tax damage.

Tax-loss harvesting is especially valuable when done at scale. Losses elsewhere in the portfolio can offset gains from the concentrated stock, making it easier to sell portions of the winner without paying the full tax cost that an unplanned liquidation would create. More sophisticated structures, including separately managed accounts and long-short overlays, can deepen that flexibility, though they require more expertise and tighter operational control.

This is one reason the article’s broader point is right: managing concentrated wealth is often too complex to do casually. It requires not just investment views, but coordination across brokerage accounts, 401(k)s, Roth accounts, cash reserves and sometimes alternative structures. The portfolio has to be viewed holistically. Looking at each account in isolation usually misses the actual allocation problem.

That holistic view also changes how diversification is defined. If an investor already holds enormous exposure to one U.S. growth company in a taxable account, there may be good reason to use retirement accounts to overweight what the portfolio lacks, international stocks, fixed income, alternatives, real estate, or other diversifiers, rather than mindlessly duplicating the same growth exposure everywhere else. Diversification is not simply “own more funds.” It is intentional imbalance used to correct existing imbalance.

None of this eliminates the emotional challenge. Concentrated winners are hard to trim because they feel like proof of good judgment, good fortune or both. Selling part of the position can feel like disloyalty or fear. Yet the point of wealth management is not to honor the stock. It is to protect the life the stock has made possible.

That is the real case for at least partial diversification. Wealth should eventually create peace of mind, not permanent vigilance. If a portfolio has become so concentrated that the owner cannot enjoy it without constantly worrying about one company’s earnings, valuation or next drawdown, then the portfolio is no longer serving its purpose well.

This is where the standard diversification rule breaks down in an important way. For ordinary investors, broad diversification is usually the beginning. For concentrated winners, diversification is often the translation step, the process of turning extraordinary paper wealth into a structure that can actually support a lifetime of spending, giving, legacy and emotional calm.

So no, full diversification is not always totally necessary. Not immediately, not mechanically, and not at any tax cost.

But some diversification usually is. The goal is not to erase the stock that made you wealthy. The goal is to make sure your life no longer depends on it.

You should always consult a financial, tax, or legal professional familiar about your unique circumstances before making any financial decisions. This material is intended for educational purposes only. Nothing in this material constitutes a solicitation for the sale or purchase of any securities. Any mentioned rates of return are historical or hypothetical in nature and are not a guarantee of future returns.

Past performance does not guarantee future performance. Future returns may be lower or higher. Investments involve risk. Investment values will fluctuate with market conditions, and security positions, when sold, may be worth less or more than their original cost.