Sell Your RSUs at Vest: The Cash-Bonus Test for Tech Workers

When RSUs vest, the rational default for almost every tech worker is the same: sell all of the shares, set aside any additional tax owed, and invest the rest into your target portfolio. The hard part is recognizing that this is a portfolio decision, not a tax decision. The simplest test:

If your employer paid you the same after-tax amount in cash today, would you immediately use it to buy your employer’s stock?

For most people, the answer is no. Holding vested RSUs is the same trade. The shares feel different because they arrived through compensation, but on the day they vest the dollars and the shares are interchangeable. The choice to keep the shares is the choice to buy that stock.

Three Choices, Side by Side

Almost every plan offers three ways to handle taxes at vest. The names are operational; the portfolio outcomes are very different.

Choice at vest	What it feels like	What it actually does
Sell all	“I’m cashing out the RSUs.”	Converts vested compensation into cash, then into your chosen target portfolio. Zero new employer-stock exposure.
Sell to cover	“I’m just paying the taxes.”	Sells only enough to fund withholding and keeps the rest as employer stock. The held shares are an investment in your employer’s stock, paid for with after-tax compensation.
Deposit cash to retain shares	“I’m avoiding selling.”	Pays withholding from outside cash and keeps every vested share. Equivalent to using money from your bank account or taxable brokerage to buy more employer-stock at the vest price.

The first choice is a portfolio reset. The other two are active employer-stock purchases dressed up as tax mechanics. Recognizing that framing is the entire decision.

Vesting Creates the Tax Bill, Not Selling

A common reason to hold vested RSUs is to avoid “creating a tax event.” The tax event already happened. RSUs become taxable when shares are delivered: the fair-market value at vest is reported as W-2 wages and is subject to ordinary income tax, Social Security, and Medicare. Selling the shares the same day adds at most a tiny short-term capital gain or loss because the cost basis is the vest-date price.

Withholding is a separate question, and the default rate is usually too low for high earners. The IRS allows employers to withhold supplemental wages at a flat 22% federal rate for the first $1 million in a year, with a 37% rate above that. Tech-worker marginal rates are often 32% to 37% federal plus state plus Medicare surcharges, so the 22% default leaves a gap that arrives as an April surprise. The Summitward guide on RSU Withholding works through the math and the safe-harbor election. The point for this post: holding shares does not avoid the tax. Selling does not create it.

Why Holding Concentrates Risk That Isn’t Compensated

Single-stock risk is diversifiable. Broad-market investors avoid it by owning thousands of companies, which means the market does not pay a premium to investors who voluntarily take it on. FINRA states the diversification case directly: “Diversification reduces the risk of major losses that can result from over-emphasizing a single security or single asset class.” FINRA: Asset Allocation and Diversification.

The empirical record is even sharper. Bessembinder’s global stock data from 1990 to 2020 finds that a majority of U.S. and non-U.S. stocks underperformed one-month Treasury bills over their lifetimes, and the top-performing 2.4% of firms accounted for all of net global stock-market wealth creation. The Summitward guide on Most Stocks Lose to T-Bills covers the data. The implication for any single position, including your employer’s, is that the broad market owns the rare extreme winners by construction; betting on any one stock to be among them is a low base-rate proposition.

The case is sharper still for employer stock specifically. Benartzi, Thaler, Utkus, and Sunstein analyzed company stock in 401(k) plans in the Journal of Law and Economics (2007) and made the canonical point: holding employer stock layers two correlated risks on top of each other. Single-security risk is one. The bigger problem is that an employee’s human capital is typically positively correlated with company performance. If the stock falls 50%, layoffs, hiring freezes, and weaker refresher grants often arrive at the same moment. Benartzi, Thaler, Utkus, Sunstein (2007). The Summitward guide on Human Capital Risk for Tech Workers works through the balance-sheet math, and Concentration Risk covers the sell-vs-hold break-even.

When Holding Some Employer Stock Is Defensible

The default of selling at vest does not mean “zero employer stock under any circumstances.” A small, deliberate position can be reasonable if it is sized under a written policy and re-evaluated each vest. Workable bands:

0% of investable assets is fully rational and is the cleanest baseline.
1% to 5% can be acceptable as a deliberate “skin in the game” allocation for someone who actively wants exposure.
10%+ needs an explicit reason and a written risk acceptance.
20%+ is the threshold the academic literature flags as concentrated, and it usually is not defensible for a household whose paycheck and career capital are already tied to the same employer.

Operational exceptions to selling immediately are real and narrow:

Trading blackout windows from the company calendar.
10b5-1 plans for executives or anyone in regular possession of material nonpublic information. A 10b5-1 plan is a pre-arranged trading schedule that creates an affirmative defense to insider-trading liability if it is adopted in good faith without MNPI. SEC’s 2022 amendments added cooling-off periods (90 days for directors and officers, 30 days for others) and require a good-faith certification at adoption. SEC: 2022 Rule 10b5-1 amendments. A 10b5-1 plan can automate disciplined diversification even when discretionary trading is restricted.
Private-company RSUs with no liquid secondary market. The decision is forced; cash flow planning matters more than allocation here. See the Summitward guide on RSU Cash-Flow Strategy for households waiting for liquidity.
Charitable giving of already-appreciated shares can be more tax-efficient than selling and donating cash. This applies to legacy positions with embedded gains, not to newly vested shares.
Very-low-tax-year planning may make deferring a sale into a sabbatical or low-income year worth the concentration cost. Specific to the household; not a default rule.

What to Do at Every Vest

Sell at vest by default. Plan the execution: market order for liquid public stock, scheduled trades inside a 10b5-1 plan if you have MNPI exposure.
Estimate the tax shortfall. Default 22% supplemental withholding usually under-collects for high-income tech workers. The RSU Withholding guide and its calculator project the gap.
Set aside the shortfall in cash. A dedicated tax-reserve sub-account avoids the next April surprise.
Invest the rest into your target portfolio. Globally diversified stock or stock-and-bond mix per your allocation, not your employer’s ticker.
Repeat every vest. A single decision to hold is rarely catastrophic; many of them in a row build the concentration that breaks households during a downturn.

Frequently Asked Questions

Doesn’t selling immediately create a tax bill?

The tax bill comes from vesting, not selling. The fair-market value at vest is W-2 wage income regardless of what you do with the shares. Selling the same day adds at most a small short-term capital gain or loss against the vest-date cost basis. Holding the shares does not avoid any tax; it converts the residual after-tax compensation into employer stock.

What if I think my company is going to outperform the market?

It might. So might any other single stock. Bessembinder’s data shows the base rate for individual stocks beating T-bills is below 50% globally. If your private read on the company is non-public material information, you cannot trade on it. If it is public or immaterial, the market is already pricing it. Familiarity with an employer is real, but it rarely produces a tradable edge after fees, taxes, and concentration risk are accounted for.

Should I hold vested shares for a year to get long-term capital gains?

Holding only changes the tax treatment of post-vest appreciation, not the original RSU income, which is already ordinary. The question is whether one year of concentrated single-stock risk is worth the difference between long-term and short-term capital-gain treatment on whatever the stock does in that year. For most households the answer is no, especially when the position is large.

I already have a large legacy employer-stock position. What do I do?

Embedded capital gains change the calculus. Selling realizes the gain at long-term rates (assuming over a year held) and recovers the diversification benefit; holding accepts more single-stock and human-capital correlated risk. A staged diversification plan that aligns sales with charitable giving, tax-loss harvesting elsewhere in the portfolio, or low-income years can cushion the tax hit. The Concentration Risk guide includes the break-even math and a multi-year diversification simulator.

Related Guides

Equity Compensation covers the full RSU / ESPP / ISO / NSO landscape and the tax mechanics across each instrument.
RSU Withholding works through the 22% supplemental rate, marginal mismatches, safe harbor, and W-4 line 4c election.
Concentration Risk covers the math of single-stock exposure and the sell-vs-hold break-even with a multi-year fan chart.
Human Capital Risk for Tech Workers frames why salary plus RSUs already double-concentrate your balance sheet on one employer.
RSU Cash-Flow Strategy shows how to use vested-RSU proceeds to fund tax-advantaged accounts on a paycheck-bridge schedule.
Most Stocks Lose to T-Bills covers Bessembinder’s evidence on why broad diversification captures the rare winners and individual stock-picking usually does not.
When to Sell a Winning Stock is the legacy-position counterpart to this guide: what to do with old YOLO winners that have appreciated, where selling triggers tax and holding compounds concentration.

Key Takeaways

The cash-bonus test resolves most RSU vesting decisions. Would you buy your employer’s stock with the same after-tax amount in cash today? If not, holding the shares is the same trade.
Sell-to-cover and deposit-cash are concentration choices, not tax strategies. They affect how taxes get paid; they do not change whether you owe them. The held shares are an active employer-stock allocation either way.
Single-stock risk is diversifiable, so the broad market doesn’t pay you for taking it on. Bessembinder shows most individual stocks underperform one-month T-bills; the broad market owns the rare extreme winners by construction.
Employer stock layers single-security risk on top of human-capital risk. Salary, career capital, refresher grants, and the local tech labor market are already exposed to one employer. The stock is an additional dose of the same risk.
Sell at vest as the default. Set written guardrails for any deliberate retention. Zero is the cleanest baseline. 1-5% can be a deliberate allocation. 10%+ should require a reason. 20%+ is the academic concentration threshold.