SpaceX IPO Tracker

Two exchanges, two instruments, and the same near-vertical cliff in the first half of October.

Kalshi prices Anthropic officially announces an IPO before Oct 1 at 24.5% and before Nov 1 at 89.0%—a 64.5-point jump across one month. Polymarket prices Anthropic IPOs by September 30 at 6.0% and by October 31 at 90.5%—an 84.5-point jump across the same month, with the September 15 leg at 0.5% and October 15 at 67.5%.

Different questions—announcing versus listing—on different venues, and both put essentially all of the probability mass in a two-week window starting October 1.

And Polymarket prices the listing above the announcement. Anthropic IPOs before 2027 marks 94.0%; Kalshi's Anthropic announces an IPO this year marks 91.5%. Announcing must precede listing, so the second number cannot exceed the first. It is only two and a half points, but the ordering is backwards.

$264,775 on Kalshi's Anthropic ladder sits on two settled legs quoted at 50.0%. Before Jul 1 holds $172,691 and Before Aug 1 holds $92,084, both resolved No, both marked 0 bid / $1.00 ask—25% of that book's $1,063,276.

Starship 14 is worse: 63% of its book is dead. Before Aug 21 and Before Sep 1 have resolved No and hold $47,188 of $74,557, both at 50.0%.

OpenAI is priced three ways and the venues are eight points apart. Kalshi: announces an IPO this year 18.5%, on $99,941 of open interest. Polymarket: IPOs before 2027 11.5%, and its market-cap board's No IPO by December 31 leg at 91.0% implies 9.0%. Polymarket also disagrees with itself by two and a half points.

The other listing on the board.

OpenAI is the second name on every IPO book and the venues cannot agree on it. Kalshi prices OpenAI officially announces an IPO this year at 18.5% on $99,940 of open interest—the second-deepest leg in that book behind Anthropic. Polymarket prices OpenAI IPOs before 2027 at 11.5% on $15,385, the busiest leg in its book. And Polymarket's separate market-cap board implies 9.0%.

Announcing is easier than listing, so Kalshi's 18.5% sitting above Polymarket's 11.5% is the right ordering—but a seven-point gap on the same calendar year is wide, and Polymarket's own two numbers are two and a half points apart from each other.

The market-cap board is where it gets specific: if OpenAI does list this year, the modal outcome is above $1.5 trillion at 5.2%, and every bucket from $500B to $1.25T prices under 1.3%.

Launch cadence, and the Starship books that do not match.

The September launch-count book turned $30,987 on $61,844 held and implies about 9.7 launches: Above 8 at 93.5%, Above 9 at 78.5%, Above 10 at 41.5%, Above 11 at 21.0%, Above 12 at 8.5%, Above 13 at 2.5%.

Its busiest rung is Above 12 at 8.5%, on $6,657—ahead of Above 9 at 78.5% ($6,540) and Above 10 at 41.5% ($5,179). The most-traded contract in the cadence book is again the one it prices least likely.

Starship 14 is priced on both venues and they are eight points apart mid-month. Kalshi: before Sep 18 43.0%, before Oct 1 87.5%, before Oct 16 96.0%. Polymarket: by September 15 22.5%, by September 26 73.0%, by September 30 91.0%. Interpolated to September 18, Polymarket reads roughly 35% against Kalshi's 43%.

Sixty-three percent of Kalshi's Starship book is settled and quoted at 50.0%. Before Aug 21 ($5,574) and Before Sep 1 ($41,614) both resolved No.

The annual reach-space book is nearly frozen: $48 of volume on $24,670 held, with 5 launches modal at 50.0% and 4 at 41.0%.

The merger book, and where its money sits.

KXCOMPANYACTIONMERGER-27 holds $742,451 and turned $5,842. Before Oct 1, 2026 prices 7.5% and holds $148,428, taking 57% of the day's volume; then Before Nov 1 8.5%, Before Dec 1 13.0%, Before Mar 1, 2027 29.5%, Before May 1 36.5%, Before 2028 59.5%.

The near end is almost flat. October at 7.5% and November at 8.5% differ by a single point, then the ladder steepens sharply—four and a half points in December, sixteen more by March. The market is saying a Tesla–SpaceX merger is not a September or October event and might be a 2027 one.

Beside it, the year-end leg on its own.

The IPO calendar the listing opened.

Anthropic dominates every board. Kalshi's named-company book gives it 91.5% to announce this year, ahead of Oura at 84.5%, Discord at 29.0%, OpenAI at 18.5%, Deel 7.5%, Rippling 7.0%. Polymarket's: Anthropic 94.0%, Discord 18.15%, OpenAI 11.5%, Remote 10.0%, Rippling 9.0%, Epic Games 4.6%.

The two venues are seven points apart on OpenAI and two and a half on Anthropic—in opposite directions. Kalshi is higher on OpenAI announcing; Polymarket is higher on Anthropic actually listing, which is the stricter event.

The OpenAI market-cap board is a third read: No IPO by December 31 at 91.0%, implying a 9.0% listing probability, on $18,375—86% of that book's day. Conditional on a listing, the board's largest bucket is 1.5T+ at 5.2%, with everything from $500B to $1.25T priced under 1.3%. It is pricing a very large debut or none at all.

And $11,470—58% of Polymarket's Anthropic day—bought the September 30 leg at 6.0%, the same near-date concentration this catalog keeps logging.

• Both venues put Anthropic's IPO in the first half of October, and both do it with a cliff. Kalshi jumps 24.5% → 89.0% between October 1 and November 1; Polymarket jumps 6.0% → 90.5% over the same month, with September 15 at 0.5% and October 15 at 67.5%.
• Polymarket prices the listing above the announcement. Anthropic IPOs before 2027 at 94.0% against Kalshi's announces an IPO this year at 91.5%. Announcing precedes listing; the ordering is backwards by two and a half points.
• $264,775 on Kalshi's Anthropic ladder sits on two settled legs at 50.0%—25% of the book. Starship 14 is worse at 63%, holding $47,188 on two resolved gates.
• OpenAI is priced three ways across two venues: 18.5%, 11.5% and an implied 9.0%. Polymarket disagrees with itself by two and a half points.
• The September launch-count book's busiest rung is Above 12 at 8.5%, in a book implying 9.7 launches.
• Kalshi and Polymarket are eight points apart on Starship 14 launching by mid-September—43.0% against an interpolated 35%.
• The Tesla–SpaceX merger ladder is flat at the near end, 7.5% in October and 8.5% in November, then steepening to 59.5% by 2028, on $742,451 held.
• If OpenAI lists this year, the board says it debuts above $1.5 trillion or not at all—5.2% on the top bucket, under 1.3% on everything from $500B to $1.25T.