SPCX · Forward model · Developer Platform · Elon case

Assumptions & reasoning

• This vertical has no history and never will have one before 2026 Q3. SpaceX closed the acquisition on August 14, 2026, six weeks into the September quarter, so not one dollar of Cursor revenue sits in any reported SpaceX quarter — the zeros across 2025 and the first half of 2026 are fact, not padding.
• The first projected quarter is nonetheless overstated. The model books 2026 Q3 as a full quarter of ownership when SpaceX owned Cursor for roughly six of its thirteen weeks, which flatters that quarter by somewhere near $0.5B and washes out entirely by 2026 Q4.
• The 2026 Q3 base is Cursor's last circulating pre-acquisition run rate expressed as a quarter, not a growth assumption: $4B annualised is $333M a month, and three of those months is $1.00B — which is what 4.17M seats at $80 comes to. Deutsche Bank's ~$12B Cursor contribution to its $100B year-end target is that same $4B tripled, and it is an extrapolation rather than a reported figure. Cursor's own year-end guide, given in April, was above $6B. This line carries the disclosed run rate; the tripling sits in Bull and Elon, where a claimed number belongs.
• Seats are backed out, price is assumed — the reverse of the usual order, and worth knowing which half to argue with. Cursor discloses a run rate above $4B and more than a million paying customers, but an enterprise customer is not a seat. The $80 blended monthly price is ours; 4.17M seats is what that price implies against the disclosed run rate. Halve the price and the seat count doubles for the same revenue, so the level here is safer than either input.
• The base case takes only a modest share of GitHub, and takes it late. Adds start at 60K seats a quarter — Cursor's own organic pace, no repositories moving — and the ramp is tuned against that organic path so that the extra seats Origin wins are worth about $0.1B a quarter by 2027 Q4, roughly 8% of the line, and compound from there. Penetration of the professional developer base sits near 15% through 2027 H1 and reaches about 25% by 2031, for roughly $2.4B a quarter. Displacing GitHub outright is worth about $4B a year at our estimate of its current run rate, and that sits in the Bull and Elon cases, not here.
• Margin starts at 5% because inference is the cost of goods here and Cursor has been buying it. Inside SpaceX it increasingly will not be, which is the acquisition's clearest operating logic — but note that internal inference consumption is NOT Terrestrial AI revenue, exactly as internal Starlink launches are not Space revenue. Do not read a rising developer margin as a bigger AI segment.
• Capex intensity is 12% falling to 6%, the lowest in the model, because the GPUs this business runs on are built and charged inside Terrestrial AI. If SpaceX ever discloses compute dedicated to Cursor, that spend belongs here and this line is understated until it does.
• The ramp is a glide, not a step, because the subscription driver has no delayed-inflection field — only startsAfterQuarters, which zeroes revenue outright and would be wrong for a business already earning $4B a year. The 2027 H2 inflection is therefore a shape we tuned, not a mechanism the engine enforces. Drag the ramp slider and it moves from the first projected quarter.
• The four cases disagree about this line more than about any other, which is the right outcome for an asset bought eight weeks ago. Bear has it at $0.97B a quarter in 2031 — below where Cursor is running today, a $60B purchase that never grew. Base reaches $2.4B, Bull $4.6B and Elon $7.8B. Nothing in the reported history constrains any of them, so read the spread rather than the point estimate.