Imagine an engineer four years into her role: RSUs arriving each quarter, a 401(k) steadily growing, and a brokerage account now carrying more employer stock than she would ever choose intentionally. Last spring, following her advisor’s guidance, she sold enough shares to bring that position back to a healthy proportion of her portfolio. Six months later, it has drifted right back to where it began. She did nothing wrong. She followed the standard guidance precisely: diversify a concentrated position.
What that guidance, it rarely acknowledges what happens when the next quarter’s vest arrives, and the one after that, for as long as she remains with the company. Diversification is often framed as a single decision. Under a vesting schedule, it becomes a recurring decision on a timetable she does not control.
Why Traditional Advice Treats This as a One Time Issue
Most commentary on concentrated stock assumes the position grew through a singular event: a public offering that finally unlocked long‑held shares, an inheritance, or a restricted stock grant that vested all at once years prior. In those situations, “diversify” means one transaction or a brief series of them, and the matter is resolved. The position shrinks and stays appropriately sized.
A vesting schedule behaves differently. As long as employment continues, new shares arrive on a fixed calendar, RSUs typically vesting quarterly or on an anniversary cadence set at grant, regardless of what happened last time. Selling down to a target allocation this quarter does not influence what the next vest deposits. And if the stock has appreciated, as every employee hopes it will, the position can rise above target even faster than the last sale reduced it. The correction was real; it simply wasn’t permanent, because the source of the concentration never paused.
Why Each Sale Quietly Becomes More Difficult
Two forces make repeating the sale each quarter increasingly challenging.
The first is simple loss aversion: watching a stock continue to climb after selling some of it feels like a misstep, even when the sale was the right move for diversification. That emotional friction makes the next sale harder, not easier.
The second is more subtle. When RSUs vest, their value is taxed as ordinary wage income, and employers typically withhold at the flat federal rate for supplemental wages, 22% on the first $1 million of such wages in a calendar year, per IRS Publication 15 that we referenced in our previous month’s article. For employees whose actual marginal bracket exceeds 22%, which includes most people receiving meaningful RSU grants, this flat rate under withholds relative to the true liability. The difference can look like extra cash sitting in the account after a vest, when part of it is already spoken for. Spending or reinvesting that amount, rather than selling additional shares to cover the shortfall, keeps the concentrated position larger than intended.
The withholding on a vest is a statutory rate, not a preview of the final tax bill. The two rarely align once income rises above the 22% bracket.
So Is It Worth It for You?
If equity compensation represents a small portion of total investable assets, or the vesting schedule is nearing its end, a final tranche, an offer that will not be renewed, handling each sale individually is a reasonable amount of effort for a problem that is naturally winding down.
The calculus shifts for anyone whose employer continues issuing new grants year after year. In that case, the position is not a one‑time imbalance to resolve; it is a continuous flow that refills itself regardless of how thoughtfully the last decision was made.
A helpful test: look at the share of total investable net worth currently sitting in employer stock, not what is planned to be sold eventually. If that number consistently drifts back toward the same level a few months after each trade, the issue is not the size of any single sale. It is that the sale is being made anew, from scratch, every time.
The most effective escape hatch is a standing sale instruction, often through a 10b5‑1 trading plan or a direct arrangement with the equity plan administrator that automatically sells a fixed percentage or share count at each vest. It transforms diversification from a repeated decision into a durable rule, which is the only structure that survives a schedule that never asks permission.
Companies sometimes extend 10b5‑1 plans to employees who are not traditionally viewed as insiders (owning more than 10% of company stock). In practice, certain roles give employees visibility into MNPI (Material Non‑Public Information), which can place them under restrictive blackout windows for trading. Offering a 10b5‑1 plan creates clarity and provides protection against any appearance of insider trading. It gives these employees a framework that aligns their trading activity with both policy and best practice, while preserving the consistency needed to manage a position that refills itself on a fixed calendar.
The question to bring to an advisor is not whether to diversify out of employer stock; anyone holding a concentrated position already knows that answer. The question is whether a standing rule, aligned with the vesting calendar itself, would maintain the target allocation automatically rather than requiring the same decision, against the same resistance, every time new shares arrive.
Disclaimer: This article is provided for educational, general information, and illustration purposes only and is not exhaustive. Diversification and/or any strategy that may be discussed does not guarantee against investment losses but are intended to help manage risk and return. If applicable, historical discussions and/or opinions are not predictive of future events. The content is presented in good faith and has been drawn from sources believed to be reliable. Nothing contained in the material constitutes tax advice, a recommendation for purchase or sale of any security, or investment advisory services. We encourage you to consult a financial planner, accountant, and/or legal counsel for advice specific to your situation. Reproduction of this material is prohibited without written permission from Martos Wealth Management, LLC, and all rights are reserved.










