RSU Tax Strategy: What Engineers Get Wrong About Equity Compensation

How RSU Taxation Works

Restricted Stock Units (RSUs) are a form of equity compensation where your employer grants you shares of company stock that vest over time, typically on a quarterly or annual schedule. Unlike stock options, RSUs have value even if the stock price drops after your grant date. But they also come with tax implications that catch many engineers off guard.

When RSUs vest, the fair market value (FMV) of the shares on the vest date is treated as ordinary income. This means it shows up on your W-2 just like your salary, subject to federal income tax, state income tax, Social Security, and Medicare. Your cost basis in the shares is set to the FMV at vest.

After vesting, any subsequent gain or loss is treated as a capital gain or loss. If you sell within one year of the vest date, the gain is short-term (taxed at your ordinary income rate). If you hold for more than one year after vesting, the gain qualifies for the lower long-term capital gains rate.

Most companies withhold taxes at the time of vesting by automatically selling a portion of your shares. The federal supplemental withholding rate is 22% for income up to $1 million and 37% above that. Combined with state and FICA taxes, companies typically sell around 40% of your vesting shares to cover the tax bill. This withholding is oftennot enough if your total income places you in the 32% or 35% federal bracket, which can result in an unexpected tax bill at filing time.

Calculate Your RSU After-Tax Value

The Sell-vs-Hold Decision

The moment your RSUs vest, you face a decision: sell the shares immediately and invest the proceeds in a diversified portfolio, or hold the company stock. Most financial advisors recommend selling immediately. The reasoning comes down to concentration risk.

As an engineer at a tech company, your human capital is already heavily correlated with your employer. Your salary, bonus, future RSU grants, and career trajectory all depend on the company doing well. Holding vested shares adds portfolio risk on top of income risk, concentrating both in a single company. If the company struggles, you could face a pay cut, layoff, and portfolio loss simultaneously.

The lifecycle asset allocation framework applies directly here. Your future earnings represent a bond-like asset (stable, predictable income), but when your employer stock makes up a large share of your portfolio, that "bond" becomes correlated with your equity holdings. Selling and diversifying restores the independence between your human capital and your financial capital.

There are legitimate reasons to hold in some cases: if you have strong conviction in the company's near-term prospects, if you want to reach long-term capital gains treatment (holding for more than a year after vest), or if the tax cost of selling is unusually high. But the default should be to diversify, and deviations from that default should be deliberate and sized appropriately. Use the Multi-Year Diversification Projection on the Portfolio page's Concentration tab to see how hold vs. diversify paths diverge over 5+ years with Monte Carlo fan charts. For a deeper look at why concentration is uncompensated risk and how to build a diversification schedule, see the Concentration Risk guide.

Tax Bracket Impact of Vesting

RSU vests are W-2 income, which means they stack on top of your salary when determining your tax bracket. For engineers with significant equity compensation, this can create bracket jumps that are easy to underestimate.

Consider an engineer earning $180,000 in base salary with $120,000 in RSUs vesting during the year. Their total W-2 income is $300,000, which pushes them from the 24% federal bracket into the 32% bracket (for a single filer in 2025, the 32% bracket starts at $197,300). The marginal tax on the last $103,000 of income jumps by 8 percentage points compared to what many expect.

For married couples filing jointly, the bracket thresholds are wider, but the same dynamic applies. Two tech workers each with substantial RSU vests can easily land in the 32% or even 35% bracket on combined income.

The gap between the supplemental withholding rate (22%) and your actual marginal rate (32% or higher) means the automatic withholding at vest time is insufficient. You will owe the difference when you file your tax return. Summitward's RSU Withholding Rate Calculator on the Tax Projection page computes the exact withholding percentage to set for your next vest, based on your YTD income and expected remaining compensation. It also shows the dollar shortfall if you are stuck at the default 22% rate.

Tax-Loss Harvesting After Diversifying

When you sell employer stock after a vest and buy diversified index funds, you create a taxable event (if the stock has appreciated since vesting). But if you hold other positions at a loss, tax-loss harvesting (TLH) can offset some or all of that gain.

Here is how it works in practice. Suppose you sell $50,000 of employer stock with a $10,000 gain since the vest date. In the same year, you have $8,000 in unrealized losses on an international fund in your taxable brokerage account. By selling the losing position and buying a similar (but not "substantially identical") fund, you realize the $8,000 loss, which offsets $8,000 of the $10,000 gain. You only pay tax on the remaining $2,000.

The IRS wash sale rule prevents you from buying back the same security within 30 days of selling it at a loss. But switching from one index fund to a similar one (for example, from a Vanguard total market fund to a Schwab total market fund) is generally acceptable. This maintains your target allocation while capturing the tax benefit.

Summitward's Tax-Loss Harvesting calculator helps you identify which lots in your portfolio have harvestable losses, estimates the tax savings, and suggests replacement funds that maintain similar exposure without triggering a wash sale.

ESPP: The Best Deal in Equity Compensation

An Employee Stock Purchase Plan (ESPP) lets you buy company stock at a discount, typically 15% off the lower of the stock price at the start or end of the offering period. This "look-back" provision means you get at least a 15% discount, and potentially much more if the stock has appreciated during the offering period.

For example, if the stock was $100 at the start of the offering period and $130 at the end, you buy at 85% of $100 = $85 per share, an effective discount of 35% off the current market price. Even if the stock is flat, you get a guaranteed 15% return on your contribution over the offering period (typically 6 months).

ESPP shares have their own tax rules. A qualifying disposition (holding for at least 2 years from the offering date and 1 year from the purchase date) gives you favorable tax treatment: only the 15% discount is taxed as ordinary income, and the rest is long-term capital gains. A disqualifying disposition (selling before those holding periods) treats the full discount as ordinary income.

Most financial planners recommend maxing your ESPP contribution and selling immediately after purchase (a disqualifying disposition). The guaranteed 15% or greater return over 6 months far outweighs the tax difference between qualifying and disqualifying dispositions. The capital at risk is small (you are holding employer stock for days, not years), and the expected return is exceptional.

Common Mistakes

1. Holding for Long-Term Capital Gains When Concentration Risk Is Higher

Many engineers hold vested RSUs for over a year to qualify for the long-term capital gains rate (15-20%) instead of the short-term rate (their marginal bracket, often 32-37%). The math sometimes favors this, but the risk often does not. If your employer stock represents more than 10-15% of your portfolio, the concentration risk you are carrying during that holding period can dwarf the tax savings. A 30% stock decline wipes out years of tax optimization.

2. Anchoring on the Grant Price

RSUs are granted at a specific stock price, and many engineers mentally anchor to this number. "My RSUs were granted at $150, and the stock is now at $120, so I should hold until it recovers." This is a sunk cost fallacy. The grant price is irrelevant to the sell-vs-hold decision. What matters is the current price, your cost basis (which is the vest price, not the grant price), and the expected risk-adjusted return of holding the stock vs. a diversified alternative.

3. Not Accounting for the Withholding Gap

The federal supplemental withholding rate of 22% is often significantly below your actual marginal rate. If your total income puts you in the 32% bracket, you are under-withheld by 10 percentage points on every RSU dollar. On $200,000 of RSU income, that is a $20,000 shortfall that shows up as taxes owed when you file. Many engineers are surprised by this and do not set aside cash to cover it. Plan for the gap by estimating your actual marginal rate and setting aside the difference.

4. Treating Unvested RSUs as Guaranteed Wealth

Unvested RSUs depend on continued employment and, in most cases, the company's continued existence as a public entity. They are not money in the bank. Including unvested RSUs in your net worth at full current market value overstates your financial position. A more conservative approach: count unvested RSUs at a discount (some planners use 50-70% of current value) to account for vesting risk, or exclude them entirely from your FI number calculation and treat vests as a bonus when they arrive.

Related Guides

Equity compensation intersects with several other financial planning strategies:

• Sell Your RSUs at Vest formalizes the cash-bonus test and compares sell-all, sell-to-cover, and deposit-cash side by side. The decision filter that resolves most vesting choices in one paragraph.
• The RSU Bridge Strategy shows how to operationally run a household on intentionally small paychecks by using RSU vests as periodic balance-sheet replenishment, with a paycheck-bridge calculator.
• RSU Withholding Calculator turns the 22%-vs-marginal gap discussed above into a per-vest recommendation with an IRS safe-harbor check and a W-4 line 4c alternative.
• Concentration Risk covers when to sell company stock and how to build a multi-year diversification plan using HHI analysis.
• Tax-Loss Harvesting shows how to offset the tax impact of selling appreciated RSUs by harvesting losses in other positions.
• Fama-French Factor Analysis reveals the hidden factor tilts that concentrated stock positions introduce to your portfolio.
• Your FI Number helps you understand how RSU income and diversification decisions affect your path to financial independence.
• Are You About to Be House-Poor? applies the RSU-vs-salary distinction to the home affordability decision: underwrite the mortgage to base salary, not total comp.

Key Takeaways

• RSU vests are taxable income. They push you into higher tax brackets and the automatic withholding often is not enough. Use Summitward's Tax Projection page to model the bracket impact of your expected vests.
• The default should be to sell and diversify. Your human capital is already concentrated in your employer. Holding company stock doubles down on that concentration. Use the Portfolio page's Concentration tab to quantify your single-stock risk.
• Tax-loss harvesting can offset diversification costs. When you sell employer stock at a gain, harvest losses elsewhere in your portfolio to reduce the tax bill. Summitward's TLH calculator identifies harvestable lots and estimates savings.
• ESPP is almost always worth maxing. The guaranteed 15%+ discount over a 6-month period is one of the best risk-adjusted returns available. Contribute the maximum and sell promptly.
• Run Monte Carlo with your actual allocation. After diversifying RSU proceeds, update your portfolio weights in Settings and run a retirement simulation to see how the reallocation affects your long-term plan.