The $1.75 Trillion IPO: What SpaceX’s Confidential SEC Filing Actually Means for Markets

In April 2026, SpaceX confidentially filed an S-1 registration statement with the Securities and Exchange Commission, setting up what is positioned to be the largest IPO in US market history. The target valuation range is $1.75 trillion to $2 trillion. The raise is reported at up to $75 billion. The listing is being discussed for June 2026. The most recent secondary-market tender, completed in December 2025, priced shares at approximately $421 each for an implied valuation near $800 billion. The IPO range is roughly twice that. On a recent episode of What Are Your Thoughts (Downtown Josh Brown and Michael Batnick’s show on The Compound), Rupert Mitchell of Blind Squirrel Macro walked through what the mechanics of an event this size actually look like in terms of underwriter syndicate, index inclusion timing, and the cross-flow with Tesla. This article anchors his framing to the confirmed reporting and lists the parts of his argument that still need independent verification.

Key facts at a glance

• SpaceX confidentially filed an S-1 with the SEC in April 2026, per CNBC’s reporting on the filing.
• Target valuation: $1.75T to $2T at IPO. Reported raise size: up to $75B, which would be more than three times the previous largest US IPO, per Bloomberg’s coverage of the prospective deal.
• December 2025 secondary-market tender priced shares at approximately $421, implying a valuation near $800B. The IPO range is more than double that.
• A February 2026 merger with xAI valued the combined entity at approximately $1.25T.
• Mitchell’s specific claims on What Are Your Thoughts include a $850M underwriter fee pool (1% commission), a $16.5B free-float threshold for adequate passive-index coverage, and a comparison to the 1998-2000 US IPO market. The historical comparison figure he cited is flagged for independent verification.

Who is Rupert Mitchell

Rupert Mitchell runs Blind Squirrel Macro, a research and newsletter outfit covering capital markets and macro flows. His framing on What Are Your Thoughts focused less on what SpaceX as a business is worth and more on what the mechanics of a $75B equity raise actually do to market structure: who underwrites, how fast index funds can buy, and what happens to the supply-and-demand balance for equities at a moment when a decade of buybacks has been shrinking the float.

What the confidential filing actually says

A confidential S-1 means the company has filed the registration statement under JOBS Act provisions that keep the document non-public until close to the marketing roadshow. The market doesn’t see the financials yet. What it does see is the structural setup: the underwriter slate, the rough size, and the target window.

The most-cited target valuation range is $1.75T to $2T. The implied raise is up to $75B. For context, the largest previous US IPO was Saudi Aramco’s NYSE-equivalent listing (Aramco listed on Tadawul, not in the US; the largest US IPO remains Alibaba’s $25B in 2014). At $75B, SpaceX’s raise alone is three times larger than Alibaba’s, per Bloomberg’s reporting.

The December 2025 tender at $421/share has become the reference price for secondary market participants. Comparing the tender to the IPO range gives a multiple expansion of roughly 2.2x in six months. Mitchell’s framing on the podcast was that this expansion is not the central story; the central story is what happens to the broader market when a $75B raise drops into it.

The Wall Street syndicate

Mitchell’s first technical argument on the show is that the underwriter syndicate is fully mobilized. By his count, the fee pool is approximately $850 million at a 1% gross spread, divided across “every major underwriter you can name.” That figure would not be possible without effectively the entire bulge-bracket plus most of the international banks signing on. For a comparison: the Alibaba IPO fee pool was approximately $300 million.

The 1% gross spread itself is notable. Standard underwriter spread on a deal of this size would more typically be 2-3% for a mid-cap and 1.0-1.5% for a mega-cap IPO. SpaceX commanding 1% reflects the bargaining power of the issuer and the strategic value to underwriters of being on the deal regardless of fee economics.

Index inclusion is the timeline that matters

Mitchell’s most technical argument concerns the timing of structural buying after the IPO. Once a stock lists, it is not immediately eligible for the largest passive index ETFs. The NASDAQ-100 has formal admission rules; the S&P 500 has methodology gates; FTSE Russell indices have their own thresholds. Typical delay between IPO and index admission for a stock of this size is 10 to 15 days.

During that delay window, there is a structural demand gap. The performance-following Wall Street accounts that announce “we own SpaceX” will be averaging up small token positions, not heavy buying. The genuine flow that supports the float is the passive-index purchase pipeline that activates once admission is granted. Until then, the prime-broker community has to warehouse the float through hedging.

The free-float threshold Mitchell cited is approximately $16.5 billion. That is the size needed before the largest index complexes (Vanguard, BlackRock’s iShares, State Street SPDR, Invesco) can take meaningful positions. Until the float settles above that level, structural support is patchy.

The Tesla cross-flow

Mitchell’s second argument is one that doesn’t appear in most IPO commentary: the structural ties between SpaceX and Tesla. Per the digest, on the show Mitchell cited a series of cross-company payments that flow through Tesla’s order book:

Flow	Approximate size	Period
xAI payments to Tesla	~$731M	early 2024 through Feb 2026
SpaceX purchase of Tesla Cybertrucks	~$131M	recent quarters
SpaceX purchase of Tesla Megapack storage	~$56M	recent quarters

Mitchell’s interpretation was that Tesla benefits financially from the Musk ecosystem in ways that aren’t separable from SpaceX. The trade implication: a SpaceX IPO that pulls retail capital toward what he called “Musk’s favorite baby” could compress Tesla’s share-price multiple as retail rotates. Mitchell framed his own positioning as short Tesla heading into the SpaceX IPO precisely because of this rotation risk.

The cross-flow figures are flagged for verification. Tesla’s SEC filings disclose related-party transactions; whether the $731M figure matches what’s reported there is worth checking against the 10-K. The $131M Cybertruck and $56M Megapack figures are at-MSRP characterizations from the podcast and have not been confirmed in Tesla’s own disclosures.

De-equitization: the decade-long backdrop

Mitchell’s broader framing is that a $75B equity raise lands at a moment when US equity supply has been structurally shrinking. For roughly a decade, the S&P 500 share count has been declining as buybacks outpace new issuance. The “de-equitization” trend has been one of the supports under US market valuations: fewer shares chasing the same earnings means higher per-share metrics.

A single $75B raise does not reverse a decade-long trend on its own. The argument Mitchell developed is sequential: SpaceX is the first of what could be a wave of large private companies coming public. Stripe, OpenAI, Anthropic, Databricks, and others sit in private markets at valuations that would each represent material IPO supply. If 2026-2027 produces several large IPOs concentrated in time, the de-equitization trend could meaningfully soften.

The risk to that argument is timing. A single large IPO can be absorbed if spread over a long enough enrollment window into the passive complex. A sequence of large IPOs in tight succession is what tests market liquidity.

What this analysis does not tell you

The confirmed facts are limited. Several of Mitchell’s specific claims deserve independent verification before being treated as definitive.

• The $34B historical IPO comparison. Mitchell argued the SpaceX raise could exceed total US IPO proceeds for 1998 through 2000 combined, which he cited as $34B nominal. Renaissance Capital and SDC Platinum data place 1999 alone at IPO proceeds far higher than that. The figure he used may refer to a narrower subset (e.g., a specific sector, post-bubble dollars, or a specific quarter). Until the source is documented, treat the comparison as directional rather than precise.
• The $850M fee pool figure. This depends on the actual gross spread, which has not been confirmed in any filing. The S-1 is confidential.
• The Tesla cross-flow figures. $731M / $131M / $56M are characterizations from the podcast. Cross-check against Tesla’s most recent 10-K related-party disclosure before publishing as fact.
• “Every major underwriter is on the deal.” Mitchell’s phrasing was not enumerated. Until the prospectus is public, the syndicate composition cannot be independently confirmed.
• The valuation range itself. $1.75T to $2T is a target range, not a struck price. Final pricing happens at the offering, and IPO pricing can move 20% in either direction from initial targets in either direction.
• Timing. “Around June” is the public reporting. Confidential S-1 timelines slip routinely. The window could open earlier or push to fall.

What to actually watch for

If the SpaceX IPO proceeds as currently described, four metrics will tell the story over the first six weeks:

1. The S-1 public filing date. Until it lists publicly, the financials, syndicate, and proposed pricing range remain confidential. Public filing is the moment the deal becomes priceable.
2. The opening-day pop or fade. A $75B raise priced at $1.75T expecting institutional money to absorb the offering will tell you how deep current demand really is.
3. Index inclusion announcements. NASDAQ-100 and S&P 500 committees will publish their inclusion decisions on their normal schedules. Mitchell’s 10-15 day delay assumption is testable.
4. Tesla’s relative performance into and through the IPO. If Mitchell’s rotation thesis is right, TSLA underperforms QQQ and SPY in the weeks before and after the SpaceX listing.

FAQ

Has SpaceX actually filed for an IPO?

SpaceX confidentially filed an S-1 registration statement with the SEC in April 2026, per CNBC’s reporting. Confidential filings remain non-public until close to the marketing roadshow.

What is the target valuation?

$1.75 trillion to $2 trillion, per Bloomberg’s coverage. The most recent secondary tender (December 2025) priced shares around $421, implying $800B at that point. The IPO range is roughly 2.2x the tender.

How large is the proposed raise?

Up to $75B. That would be more than three times the previous largest US IPO. Alibaba raised approximately $25B in 2014.

Is the SpaceX-xAI merger relevant to the IPO?

Yes. The February 2026 merger valued the combined entity at approximately $1.25T. The IPO valuation builds on that base.

What happens to Tesla around the IPO?

Mitchell’s hypothesis on What Are Your Thoughts is that retail capital rotates toward SpaceX from Tesla. The cross-flow figures he cited ($731M from xAI to Tesla; $131M Cybertruck purchase; $56M Megapack purchase) suggest Tesla benefits financially from the Musk ecosystem. The trade-off is whether the rotation effect dominates the cross-flow effect during the IPO window. This is testable by watching TSLA versus QQQ relative performance.

When does the IPO actually happen?

Around June 2026 per current public reporting. Confidential S-1 timelines slip routinely.