SpaceX and Cerebras: when their IPO lock-ups end

A lock-up keeps a company’s pre-IPO shareholders from selling for a while after it lists. When one ends, those shares can trade, and the supply that may follow is something holders watch. Most lock-ups are one date, 180 days out. Two of 2026’s biggest IPOs wrote theirs in steps, and the steps are in each company’s final prospectus (its 424B4), not in any data feed we could find.

SpaceX (SPCX)

SpaceX priced at $135 on June 11, 2026, and listed with about 13.1 billion shares outstanding (7.38 billion Class A and 5.70 billion Class B). Its lock-up has two parts. A 180-day lock-up releases in steps: 20% two trading days after its first earnings release (August 6), 7% on each of five dates from August 20 to October 24, 28% after its third quarter results (October 22), and the rest — up to 797.6 million shares — on December 8. An extra 10% would have come out in August had the stock closed at least 30% above the IPO price on five of the ten sessions before the first release; it closed between $108 and $125, so it did not.

A longer lock-up covers about 7.8 billion shares, including all of Elon Musk’s. Everyone else in it is released in steps through 2027: 20% after the fourth quarter’s results, 10% on March 18, 20% after the first quarter’s, 10% on May 17 and 20% on June 12, with the rest after the second quarter’s results. Musk’s 6.4 billion shares, nearly half the company, stay locked until June 12, 2027, with no early release.

Cerebras (CBRS)

Cerebras priced at $185 on May 13, 2026. Its employees could sell 2.5 million shares on the first trading day and another 2.5 million on the second, because the first day’s close ($311.07) cleared the trigger of 133% of the IPO price. Directors, officers and other holders were released in steps after each quarterly report and on six dates from August 19 to October 28. Every remaining locked share is free on November 9, 180 days after the prospectus, or on the second trading day after Cerebras reports its third quarter, if that comes first.

Reading a lock-up schedule

Every figure in a schedule is “up to”: it is what holders may sell from that day, not what they will sell. Underwriters can also waive a lock-up early. Dates tied to an earnings release are set by the release itself: SpaceX’s step after its third quarter came on the second trading day after its October 20 report.

Both schedules are on each company’s page, with the next unlock first: SPCX and CBRS. Dates that wait on an earnings release fill in when the company files it.