The stock keeps vesting. How concentrated is too concentrated?

Start with the fact that reframes everything: an RSU is taxed as ordinary income the day it vests, at its value that day. Holding the shares afterward has the same economics as receiving cash and immediately buying your company's stock with it. Nobody who received a cash bonus would put the entire bonus into one stock every quarter, yet that is precisely what holding every vested share amounts to. The variable that decides how much is too much is not the stock's prospects. It is what fraction of your future already depends on this one company.

Why is a single stock different from the market?

Because most individual stocks are worse than the index they live in. The market's long-term return is driven by a small minority of extraordinary winners; the median stock underperforms, and a meaningful share of large companies eventually suffer a drawdown they never recover from. Owning the market gets you the winners by construction. Owning one company is a bet that yours is among them, made with money you cannot afford to be wrong about, by someone whose salary, bonus, unvested grants, and professional network are already riding on the same outcome.

So what is the number?

A common rule of thumb caps any single stock at ten to fifteen percent of investable assets, but for an executive the honest ceiling is usually lower, because the rule of thumb ignores your human capital. Your paycheck is a bond issued by your employer. Your unvested pipeline is a call option on the same name. Count those honestly and a portfolio that looks twenty percent concentrated is often closer to half your economic life on one ticker. We would rather define it by consequence: the position is too large when a fifty percent decline, which happens to good companies with some regularity, would change your family's plans.

What does managing it actually look like?

For most executives, the clean baseline is selling RSUs at vest, since vest-date taxation means selling immediately adds little or no additional tax, and directing proceeds into a diversified portfolio. Around that baseline: tax-aware selling of older appreciated lots, charitable gifting of the lowest-basis shares, and for insiders, a Rule 10b5-1 plan that automates the schedule. The mechanics matter less than the decision to have a policy at all, because the alternative is deciding share by share, forever, with your judgment clouded by loyalty and recency.

The honest case for holding some

Conviction is not irrational, and some concentration is a defensible choice, made in a size you can afford to lose. There are also real frictions: blackout windows, ownership guidelines for senior officers, a large embedded gain in old lots. These shape the pace of diversification. They are not arguments against having a plan.

The principle to carry

Holding is buying. Once that sentence feels true, the rest is engineering: pick the ceiling, automate the path down to it, and let the plan do what willpower will not.

Aspirean builds diversification plans for executives whose net worth and paycheck share a ticker symbol. If your vested position has quietly become the plan, that is the moment to talk.

This piece is general education, not individual advice. Whether any of it applies to you depends on your specifics, which is exactly the conversation to have before acting.