The popular take on a Tesla SpaceX merger is that it is a question of whether. The filings say it is a question of price, and the price has an awkward property. At Friday’s closes, Tesla shareholders would need a premium of roughly 40% just to own half of a combined company, and a 39% premium is also the level at which Tesla’s market value crosses $2 trillion: the first market-capitalisation milestone in Elon Musk’s 2025 CEO Performance Award. That award, according to Tesla’s own 2025 proxy statement, is judged “solely on the basis of market capitalization” in a change in control, with the deal price counting as the share price. So the premium that makes the deal fair to Tesla’s public holders sits almost exactly on the line that starts paying Musk. SpaceX (NASDAQ: SPCX) closed Friday, 18 September, at $152.71 and Tesla (NASDAQ: TSLA) at $364.27, per Nasdaq. On the share counts in each company’s latest SEC filing, that is $2.01 trillion for SpaceX against $1.44 trillion for Tesla, a 40% gap that has widened from about 20% at the June IPO.
Having tracked every Musk related-party deal since SolarCity, I think this is the part the “90% odds” crowd skips. The 2016 SolarCity deal survived seven years of litigation because Tesla’s board could show a fair process and a fair price, and because the price was low: a 3.4% premium, per Fortune. A Tesla SpaceX merger runs the other way. Here Tesla is the company that needs the premium, and Musk owns a bigger slice of the buyer (46.0% of SpaceX’s shares) than of the target (19.9% of Tesla). Every point of premium moves value from SpaceX holders, Musk most of all, to Tesla holders, and may also unlock Musk’s Tesla shares. Tesla’s board would be pricing a deal in which the man across the table has good reasons to want the price both higher and lower.
Key facts: Tesla SpaceX merger
- SpaceX market value about $2.01 trillion (13.18bn shares × $152.71) vs Tesla about $1.44 trillion (3.95bn shares × $364.27), 18 Sep 2026 closes. SpaceX 10-Q; Tesla SEC share count
- Musk owns 6.07bn SpaceX shares (46.0% of shares outstanding) with 82.4% of voting power at IPO. SpaceX prospectus, June 2026
- Musk owns 699,580,882 Tesla shares, or 19.9%, excluding 423,743,904 performance-award shares. Schedule 13G/A, 17 Jun 2026
- Kalshi prices a binding merger agreement before 2028 at 73% and before 2027 at about 20%. Kalshi, 21 Sep 2026
- SpaceX bought $329 million of Tesla Megapacks in the first half of 2026, after $506 million of Megapacks and $131 million of Cybertrucks through 2025. SpaceX 10-Q
- Tesla’s bylaws require 3% of shares, about $43 billion at Friday’s close, to bring a derivative suit. Tesla 8-K, May 2025
What’s actually happening with the Tesla SpaceX merger talk, and why now
Nothing has been announced. No filing from either company mentions a combination agreement, and the SpaceX prospectus does not describe one. What has changed is Musk’s own language. On Tesla’s second-quarter call on 22 July he declined to rule a deal out. “As you can tell from the many collaborations on so many fronts with SpaceX, there’s more and more overlap,” he said, before adding, per Reuters: “We can’t talk about, you know, combining companies and that kind of thing on an earnings call. It’s got to be done with the appropriate process.”
Last week he went further at the All-In Summit, sitting beside SpaceX president Gwynne Shotwell. Asked why the two companies remain separate, he answered that there is “so much close collaboration in so many areas”, per Benzinga‘s account of the All-In Podcast episode, which passed 1.1 million views in a week. Shotwell had set the tone in June, telling CNBC on IPO day that a combination “might make Elon’s life a little easier, actually,” per Fortune.
The operational ties are already real and disclosed. The companies are jointly building Terafab, the chip plant in Austin. SpaceX’s 10-Q records Tesla as a related-party supplier of Megapacks and Cybertrucks, and Teslarati reports that Tesla holds a stake in SpaceX of under 1%, left over from its xAI investment. A useful analogy is a family firm with two operating companies that already share a canteen, a warehouse and a finance director: merging them looks like tidying up paperwork, until someone has to decide which family branch gets how many shares.
The obvious “90%” figure needs correcting. It is widely quoted as Musk’s own estimate. It is not. Reuters attributes it to Gene Munster of Deepwater Asset Management, a Tesla investor, who said after the July call: “I would put the odds that these two will combine at 90% today. If you were going to ask me yesterday I would have said it’s 80%.”
Quick Take: Musk has moved from silence to open hints, and the companies already trade with each other. But no agreement, special committee or proxy exists, and the most-cited “90%” is an investor’s guess, not Musk’s.
How the market, analysts and the companies are responding
Wall Street is split between inevitability and caution. Stifel wrote that “many investors consider it inevitable that Musk will move to combine SpaceX with Tesla — for them the question is not if but when,” per Reuters. JPMorgan called the “operational integration between the two entities” already “deep”, but flagged a “practical bottleneck” in regulatory approvals, particularly in China, where SpaceX’s US defence work could meet Tesla’s Shanghai operations.
Morningstar supplied the number that matters most for Tesla holders. In a June analysis, its analysts wrote that “Tesla shareholders may agree to a deal that gives Tesla at least 50% of the combined company,” and that their own fair-value estimates imply a 66%-34% Tesla/SpaceX split. The same note put SpaceX’s fair value at $63 a share, well under Friday’s $152.71. Jefferies, per Teslarati, estimated that Musk could keep about 55.3% voting control in a no-premium deal.
The companies themselves have stayed formal. Tesla general counsel Brandon Ehrhart answered on the July call by calling SpaceX a “great partner” that provides “numerous beneficial transactions”, per Reuters. The prediction markets agree with the analysts on direction but not on timing. Polymarket puts an announcement by 31 December 2026 at 19.5% and by the end of 2027 at 65.5%. Kalshi’s equivalent contracts sit at about 20% and 73%.
Retail sentiment runs hotter. On X, the most-engaged post on the topic this week argued that Musk has been “waiting for the valuation gap between $SPCX and $TSLA to be large enough” to make an offer that rewards loyal Tesla holders. The Electrified YouTube channel pointed out that Tesla has until December to hold this year’s annual meeting, since last year’s was on 6 November 2025, which would give a proxy vote a natural slot. That timing is speculation, not a disclosed plan. Columbia Business School’s Michael Ewens put the structural point plainly to Yahoo Finance: “SpaceX’s balance sheet means that any merger will be a stock deal. If it were cash, Tesla shareholders would have much less to worry about.”
Tesla SpaceX merger math: the premium, the split and the $2 trillion line
Here is the data synthesis that I have not seen in any of the coverage. Take Friday’s closes and each company’s share count from its latest SEC filing: 3,949,547,394 Tesla shares and 13,181,779,945 SpaceX shares (7.70bn Class A plus 5.49bn Class B). The at-market exchange ratio is 2.385 SpaceX shares per Tesla share. At that ratio Tesla holders would own 41.7% of the combined company.
For Tesla holders to reach Morningstar’s 50% floor, the ratio has to rise to 3.34, a 39.9% premium. That implies $509.68 per Tesla share, about 2% above the stock’s 52-week high of $498.83. Separately, the 2025 CEO award’s first tranche (35,311,992 shares) needs a $2 trillion market value. Divide $2 trillion by Tesla’s share count and you get $506.39 a share, a 39.0% premium. The two thresholds are less than one percentage point apart.
| Premium to Tesla’s 18 Sep close | SPCX shares per TSLA share | Implied TSLA price | Tesla holders’ share of combined company | Tesla value vs $2T award line |
|---|---|---|---|---|
| 0% (at market) | 2.385 | $364.27 | 41.7% | $1.44T, below |
| 20% | 2.862 | $437.12 | 46.2% | $1.73T, below |
| 30% | 3.101 | $473.55 | 48.2% | $1.87T, below |
| ~40% | 3.338 | $509.68 | 50.0% | $2.01T, at the line |
| 172% (Morningstar 66/34) | 6.479 | $989.37 | 66.0% | $3.91T, four tranches |
Source: FinanceFeeds calculation from Nasdaq closing prices and SEC share counts; tranche thresholds from Tesla’s 2025 proxy. Tesla holders’ share includes Musk’s Tesla stake.
Whether a SpaceX takeover of Tesla would count as a “change in control” under the award’s definition is not something any filing has tested. The proxy does not address a deal with another Musk-controlled company, so a Tesla special committee and its lawyers would have to answer that. If it does count, the award text is explicit: the administrator measures market value using “the greater of (i) the most recent closing price per share immediately prior to change in control and (ii) the per share price … received by the Tesla’s shareholders”, and “Any Unearned Shares that do not become Earned Shares as a result of the change in control are automatically forfeited.” At a 39% premium, one tranche would be worth about $12.9 billion at Friday’s price, before the $334.09-per-share offset the award applies.
Musk’s economics point in two directions. His SpaceX stake is worth about $927 billion and his Tesla stake about $255 billion. A higher Tesla premium dilutes the first and enlarges the second. At market terms his combined economic stake would be about 34.2%. The forfeiture clause pushes the other way: any tranche the deal price does not reach disappears for good, so a cheap deal destroys most of the award.
| Case for Tesla holders | Case against |
|---|---|
| Exposure to Starlink, launch and SpaceX’s AI business, which Tesla holders cannot own today without buying SPCX | A stock deal at market gives them 41.7% of a company whose larger half trades at 2.4× Morningstar’s fair value |
| Removes related-party friction: Megapack sales and Terafab become internal transfers | Musk’s voting control moves from 19.9% at Tesla to a majority in the combined entity, per the Jefferies estimate |
| A disinterested-holder vote and special committee would be required to defend the deal, as with SolarCity | Texas law and Tesla’s 3% bylaw make any later legal challenge far harder than in 2016 |
Quick Take: At market prices, Tesla holders get about 42%. Getting them to 50% takes roughly a 40% premium, which is almost exactly what lifts Tesla past the $2 trillion award line. Fairness and pay are priced on the same number.
Regulatory landscape: why this is not 2016 in Delaware
SolarCity is the precedent everyone cites, but the legal ground has moved. That deal was litigated in Delaware under the “entire fairness” standard. Tesla’s disinterested holders approved it, with more than 85% of shares voted in favour excluding Musk and affiliates, per Tesla’s November 2016 8-K. Vice Chancellor Joseph Slights found it entirely fair in April 2022, and the Delaware Supreme Court affirmed on 6 June 2023. The court leaned on the deal’s structure, calling a non-waivable majority-of-the-minority vote a strong fairness signal “because it disables the power of the majority stockholder to both initiate and approve the merger,” as quoted by Dechert.
Tesla is now a Texas corporation. Texas Senate Bill 29, signed on 14 May 2025, lets boards use a committee of independent directors to approve transactions with a controlling shareholder, and lets public companies ask the Texas Business Court to rule on that committee’s independence in advance, per Gibson Dunn. Tesla adopted the law’s optional 3% ownership threshold for derivative suits on 15 May 2025. At Friday’s price that is about 118.5 million shares, or roughly $43 billion. Under that bylaw, few holders besides Musk and the largest index managers would meet the bar to sue on the company’s behalf.
That shifts the protection from the courtroom to the ballot. Tesla holders would still vote, because Musk’s 19.9% is not a majority. SpaceX holders, by contrast, would have little say: the prospectus states Musk will “have the power to control the outcome of matters requiring shareholder approval.” Antitrust looks less of an obstacle, since the two companies sell different products, but JPMorgan’s China warning and US national-security review of SpaceX’s government contracts remain open questions. Morningstar raised the same point: Tesla’s “major auto and battery operations in China” could invite scrutiny of a combined supplier to the US military.
What happens next: three predictions
1. Any announced deal will lean on the SolarCity playbook. Because Delaware cleared SolarCity largely on process, and Texas now rewards independent committees with a statutory safe harbour, expect Tesla to form a special committee and seek a Texas Business Court independence ruling before any price is set. If a combination is announced without a majority-of-the-minority vote condition, treat it as a warning sign.
2. The negotiated premium will cluster near 40%, and that is where the controversy will be. A board cannot credibly offer Tesla holders less than the roughly 42% they get at market, and Morningstar’s work suggests institutions will push for half. That lands at the $2 trillion threshold. Proxy advisers will ask whether the committee priced the deal to be fair or to clear the award line, and the committee’s fairness opinion will need to show that the two numbers coincide by accident.
3. Timing will follow the relative share prices, not the calendar. Every percentage point that SpaceX gains on Tesla cuts the premium Tesla holders would need. The gap has already widened from about 20% at the June IPO to 40% today. Prediction markets price a 2026 announcement at only about one in five, so the more likely window is 2027, once Starship’s rapid-reuse target, which Musk has pointed to for next year, is either met or missed.
The simplest forward-looking read is this: the Tesla SpaceX merger debate has moved from “will they” to “at what ratio”, and on today’s numbers the answer to “at what ratio” is also the answer to “does Musk’s award start paying out.”
Frequently asked questions
Is a Tesla SpaceX merger officially announced?
No. As of 21 September 2026 neither company has announced or filed a merger agreement. Musk has hinted at it, telling Tesla’s July earnings call that any combination would need “the appropriate process,” and prediction markets price an announcement before the end of 2026 at about 20%. Until a definitive agreement is filed with the SEC, all terms discussed are estimates.
What exchange ratio would a Tesla SpaceX merger use?
At Friday’s closes the market ratio is about 2.385 SpaceX shares per Tesla share, which would give Tesla holders about 41.7% of the combined company. Any deal would likely add a premium. Giving Tesla holders 50%, the floor Morningstar thinks they may demand, requires roughly 3.34 SpaceX shares per Tesla share.
How much of each company does Elon Musk own?
Musk holds about 6.07 billion SpaceX shares, roughly 46% of shares outstanding and more than 80% of the vote through Class B stock. At Tesla he holds 699.6 million shares, or 19.9%, excluding his unearned 2025 performance-award shares. At market terms his economic stake in a combined company would be about 34%.
Would a merger trigger Musk’s Tesla pay package?
Possibly. Tesla’s 2025 proxy says that in a change in control, award milestones are judged only on market value at the deal price. The first milestone is $2 trillion, about $506 per Tesla share. Whether a combination with SpaceX counts as a change in control under the award’s definition has not been tested in any filing.
Can Tesla shareholders block a SpaceX merger?
Yes, through a vote, since Musk owns 19.9% of Tesla rather than a majority. Suing afterwards is much harder than in the SolarCity era: Tesla is incorporated in Texas and its bylaws require 3% of shares, about $43 billion at current prices, to bring a derivative claim.
How is this different from Tesla’s SolarCity deal?
In 2016 Tesla bought SolarCity for $2.6 billion in stock at a 3.4% premium, and Musk owned about 22% of each company. Here the sums are thousands of times larger and Musk owns far more of SpaceX than of Tesla, so a higher Tesla premium costs him on one side and may pay him on the other.
Related coverage: Elon Musk’s net worth at $929 billion · Tesla stock prediction: $500 bull, $250 bear · SpaceX stock surge and the Oppenheimer unlock call · Tesla Roadster’s 1 October demo
