Most investors know the feeling. You bought a position years ago, it's grown significantly, and now you're sitting on a large, unrealized gain — and you're not entirely sure you'd still buy it today. However, selling means handing a meaningful portion of that gain to the IRS. So, you hold. And hold. And hold. The question is whether that's a rational decision or a behavioral one dressed up as math.
The hard part is that both answers can be right depending on your full context, and that's what makes this one of the more genuinely difficult decisions in financial planning.
Let's start with what's actually happening when you hold a position to defer taxes. You're essentially borrowing money from the government — the tax owed — and keeping it invested. That's not nothing. If you owe, say, $100,000 in capital gains tax and you defer that for ten years with a reasonable rate of return, the deferral itself has real value. So, holding isn't irrational on its face. The math can support it.
However, the math only supports it if the position you're holding continues to perform well. That's the part people tend to gloss over. The embedded gain doesn't protect you from future losses. A position with a $500,000 gain can still fall 40 percent, and when it does, you'll have lost far more than the tax you were trying to avoid. The tax deferral only wins if the position cooperates.
For example, consider someone holding a single concentrated stock with a $600,000 unrealized gain. They're reluctant to sell because the tax bill would be substantial — let's say $120,000. But when you ask them if they'd buy that stock today, at this price, in this concentration, the answer is often no. That's the more revealing question. If you wouldn't build the position from scratch today, you're essentially holding it for tax reasons alone. That's the tax tail wagging the investment dog.
The only point we would make here is that tax deferral and investment quality are two separate conversations that often get collapsed into one. You can hold a position because you genuinely believe in its future prospects. You can also hold a position because selling feels too painful. Those are very different decisions, but they can look identical from the outside — and sometimes from the inside.
If we know your risk capacity, your time horizon, and how concentrated this position is relative to your overall financial picture, then we can start to answer whether holding makes sense. For someone with substantial other assets, deferring a gain on one position is a reasonable strategy. For someone where that single position represents the majority of their financial life, the risk of continued concentration may far outweigh the tax benefit of deferral. Behavior tends to drive the decision in the first case; math should drive it in the second.
There are also practical tools worth considering — systematic partial sales over multiple years, charitable giving strategies like donor-advised funds, opportunity zone investments, or even borrowing against the position rather than selling. None of these are universally right, but they expand the range of outcomes available to you.
The broader issue is that taxes have a way of making people passive. The reluctance to recognize a gain keeps people in positions they've outgrown, in concentrations they'd never accept voluntarily, sometimes for years longer than is sensible. Deferral is a feature of the tax code, not a requirement. Treating it as an obligation — something you must take advantage of at all costs — can quietly undermine the flexibility and control you've spent years building.
The decision to hold or exit a large taxable position is rarely obvious. But it should at least be deliberate.