SpaceX went public in June. What the December window decides for the people who built it.

• Space Exploration Technologies Corp. priced its initial public offering at $135 a share on June 11, 2026 and began trading on Nasdaq as SPCX on June 12, 2026.
• Shares held by employees and other pre-IPO holders are under a 180-day lockup that ends December 8, 2026, with staged releases before then.
• The prospectus sets out the staged releases. The first was August 6, the second full trading day after the second-quarter earnings report of August 4. A second, price-based release needed the stock to close at $175.50 or higher, 30 percent above the $135 offer price, on at least five of the ten trading days ending August 4. It was not met.
• Time-based releases follow at 70, 90, 105, 120 and 135 days after pricing, which is August 20, September 9, September 24, October 9 and October 24. October 24 is a Saturday, so those shares can first trade on Monday, October 26. One more release comes on the second full trading day after the third-quarter earnings report, and the full release is December 8. SpaceX said on October 16, 2026 that it would post its third-quarter results after the market close on Tuesday, October 20, 2026. Counted from that date, the second full trading day is Thursday, October 22, 2026. The prospectus ties that release to the report date, not to a calendar date. By the prospectus schedule, most employee shares released up to 20 percent on August 6 and 7 percent on each of the five dated releases. 28 percent follows the third-quarter report, and the rest comes December 8. How much of your own holding each date covers depends on your grants.
• Elon Musk’s shares are locked for 366 days, until June 12, 2027, a Saturday, with no scheduled early release. Certain other shareholders agreed to keep part of their shares locked longer, with staged releases from the fourth-quarter 2026 earnings report through the second-quarter 2027 earnings report.
• After every release, current employees remain subject to SpaceX’s insider trading policy and any trading windows it sets. A lockup release is not the same as an open window.
• SpaceX employs people in Hawthorne, California, on the Space Coast in Florida, at Starbase in Texas, and in Washington, among other locations. This page is written for all of them.

Source: SpaceX IPO prospectus (Form 424B4), SEC EDGAR, filed June 12, 2026, closing prices from Nasdaq, and SpaceX’s investor release of October 16, 2026. We have no relationship with the company and no non-public information. The dates, percentages and terms above come from the filings and releases named here, as of the facts-checked date. They can change after that date, so confirm your own tranches, dates and trading windows with the company’s equity team before you act.

A lockup release lifts the IPO restriction on a slice of your shares. It does not open your employer’s trading window. Each date lets a slice of your shares be sold under the lockup agreement. Whether you can actually sell that week depends on the company’s trading windows, which usually close in the weeks before an earnings report and reopen a few days after. SpaceX announces its earnings dates on its investor site, so the calendar matters more than the percentages.

Most of the tax was decided before you sell. RSUs were taxed as wages the day the shares were delivered to you, at their value that day, and the federal withholding was most likely the 22 percent supplemental rate, or 37 percent on the part of a year’s supplemental wages above one million dollars. If your real rate is higher, you owe the difference, and waiting until April to pay it can add an underpayment penalty. Your state may want its share separately. When you sell, the gain or loss is measured from the value on the day the shares were delivered, not from zero. Options are different. Exercising a nonqualified option creates ordinary income on the spread that day, and exercising an incentive stock option can create alternative minimum tax with no cash to pay it.

The decision that decides the most is how much of your net worth stays in one stock after the window opens. A plan made before the last releases tends to be better than a decision made on December 8, when everything can be sold. Anyone who may hold material non-public information, and every director and officer, should know that a 10b5-1 trading plan needs a cooling-off period before its first trade: at least 90 days (and as long as 120) for directors and officers, and 30 days for other employees. A plan only protects you if you adopt it at a time when you hold no inside information. A plan meant to trade in December has to exist well before then. For anyone who is not a director or officer, that means adopting it at least 30 days before the first trade, so by early November for December 8, and only if the company allows plans during the lockup.

1. Which lockup tranches apply to my shares, and on which dates does each one release?
2. When are the company’s open trading windows between now and the end of the year, and do I hold anything that keeps me out of them?
3. Of what I hold, how much is settled RSU shares, RSUs still vesting, options, and shares bought in a tender offer? Each is taxed differently.
4. What is my cost basis for each lot, and which lots have I held for more than a year?
5. What did the withholding at vest cover, and what will I still owe beyond it, federal and, in California, state?
6. If I hold options, what would exercising this year do to my ordinary income or my AMT, and when do they expire?
7. How much of my net worth is in SPCX today, and what number would I be comfortable with a year from now?
8. Do I need a 10b5-1 plan, and if so, by what date does it have to be adopted for a December trade?
9. What cash will I need in the next two years, for taxes, a home, a year of runway, and how much of it has to come from this window?
10. Should I be making estimated tax payments this year, and what does the safe harbor look like for me?
11. Are there charitable gifts of appreciated shares, or gifts to family, that make more sense before year-end than after?
12. What is my plan if the stock is far lower, or far higher, in December than it is today?

Nobody at the company is paid to answer these for you. The equity team will tell you the mechanics. Your CPA will handle the return. The person who puts it all on one page, in the order it matters, is usually missing. That is the gap we fill.