Before you sell, list every lot you hold with its share count, its basis, and the date its holding period turns long-term. Then pick the lots that add the least tax this year and that leave the clocks you want for next year.
This applies to any stock you got from more than one vest, including SPCX. It is not tied to SpaceX.
Your shares are not one pile
Each vest is its own lot. At vest, the fair market value counts as W-2 income for that year, whether you sell or hold. That value is the lot’s basis. Each lot’s holding period starts the day after its vest date. It turns long-term once you have held it for more than one year.
So 4,000 shares from four vests are four separate choices. Selling “4,000 shares” without naming lots lets the broker pick for you.
Three ways to order lots
| Order | What it does this year | Watch out for |
|---|---|---|
| Highest basis first | Smallest gain, or a loss, per share sold | May sell short-term lots and keep low-basis lots for later |
| Long-term lots first | Gain gets long-term treatment | Long-term lots often have the lowest basis, so the gain per share can be larger |
| Lots with a loss first | Loss can offset other gains this year | Check wash-sale rules if you buy or vest more shares within 30 days before or after the sale |
| Broker default (often first in, first out) | Sells the oldest lots | May not match the plan you wrote |
No order is right for everyone. The best one depends on your income this year, your income next year, and when each clock turns.
How to sell the lots you chose
Tell your broker which lots to sell when you place the trade. Most stock plan sites let you pick lots on the sell screen, or set a default method. Save the trade confirmation that names the lots.
Example (made-up numbers)
Example only. Not a real person and not a Lakefolio result. Price today: $150.
| Lot | Shares | Basis | Long-term? | Gain per share today |
|---|---|---|---|---|
| A | 1,000 | $90 | Yes | $60 |
| B | 1,000 | $135 | No, turns long-term in 2 months | $15 |
| C | 1,000 | $160 | No | –$10 (loss) |
| D | 1,000 | $145 | No | $5 |
Morgan wants to sell 2,000 shares this year.
- Selling A and B first books $75,000 of gain, part long-term and part short-term.
- Selling C and D first books –$5,000 net: a $10,000 loss and a $5,000 gain. Lot B can wait two months and turn long-term.
Same 2,000 shares, a very different year. Morgan should still run the full year with a tax adviser before the trade.
FAQ
Does the broker pick lots for me?
Yes, if you don't. Most use first in, first out by default. Choose lots on the sell screen, or change the default before you trade.
Do shares withheld at vest count as a lot I sold?
Shares held back to cover tax at vest are not a sale you chose. The shares left in your account form that vest's lot.
Should I always sell long-term lots first?
No. Long-term lots often have the lowest basis and the largest gain per share. Compare the tax on each choice.
Is withholding at vest the tax I owe?
No. Federal supplemental withholding is 22%, or 37% on supplemental wages over $1 million in a year (IRS Pub. 15). That is a withholding rate, not your tax rate.
Does my state change the order?
It can. States tax gains in different ways. California and Texas, for example, treat them very differently. Ask a tax adviser in your state.
More guides: When to sell RSUs · RSU tax if I sell this year · Lockup expiration: what to do · When to sell concentrated stock · SpaceX lockup dates: what to decide before each unlock · All guides
Sources
- IRS Publication 525, Taxable and Nontaxable Income (restricted stock / RSU income at vest)
- IRS Publication 550, Investment Income and Expenses (basis, holding period, identifying shares sold, wash sales)
- IRS Publication 15 (Circular E), supplemental wages
- SpaceX Form 424B4, June 11, 2026 (listing and lockup context only)
Lakefolio is educational software, not tax, legal, or investment advice.