Anthropic filed for its initial public offering on October 26, 2026. Its S-1 describes the companies on the other side of its largest contracts: the cloud providers that invest in it and resell its models, and the chipmakers and data-center operators it rents compute from. Most of them are public and report the same deals in their own filings, often without using the name.
We read the S-1 against the latest 10-Qs, 10-Ks, results releases and earnings calls of Alphabet (GOOGL $316.80 -1.06%), Amazon (AMZN $249.09 +0.44%), Broadcom (AVGO $329.17 +2.33%), SpaceX (SPCX $146.90 -0.40%), Microsoft (MSFT $532.60 +1.54%), Nvidia (NVDA $216.00 +2.39%), AMD (AMD $531.28 +2.80%) and Salesforce (CRM $247.61 -0.39%), and matched each deal from both sides: amount, date, terms and value.
Three results stand out. Alphabet's $40 billion commitment to "a private company" and Broadcom's $42 billion of convertible notes from "a customer" have the same amounts, dates and terms as Anthropic's agreements with Google and Broadcom. Both deals were reported in the press at the time; the S-1 now gives Anthropic's side of the terms, and it leaves out parts its partners disclosed. SpaceX's largest new customer, 34.5% of its third-quarter revenue, has the profile of Anthropic's cloud contract. And Amazon, the one partner that names Anthropic throughout, values the same $6.2 billion of Anthropic notes at $97.9 billion while Anthropic carries them at $108.6 billion. The rise in that liability is the entire $72.4 billion fair-value charge behind Anthropic's first-half loss.
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At a glance
| What the counterparty filed | What Anthropic's S-1 says | How they match |
|---|---|---|
| Alphabet, Q1 10-Q: in March 2026, "a $40.0 billion investment in a private company", $10.0 billion committed and $30.0 billion contingent on milestones | March 2026: Google agrees to buy 38.6 million Series G-2 shares for about $10.0 billion and may fund up to $30.0 billion more through 2030, tied to compute and revenue conditions | Same month, amounts and structure |
| Alphabet, Q2 10-Q: $20.0 billion of future funding for "a private company", milestones through 2030 | May 2026: Google's $10.0 billion Series H purchase cuts the $30.0 billion to $20.0 billion | Same amount and end date |
| Broadcom, Q3 10-Q: "our customer" may issue Broadcom up to $42 billion of convertible notes, solely for its lease obligations | Up to $42.0 billion of notes to Broadcom, solely to finance rent under the 2026 Broadcom lease | Same amount and purpose |
| Broadcom, June 10-Q: Apollo took over rack purchase agreements and "the related lease agreements with a customer"; Broadcom backstops those lease payments, up to $29 billion | "In the second quarter of 2026, Broadcom assigned a portion of its rights under one of the master equipment leases to another third party" | Same quarter; the S-1 names neither Apollo nor the backstop |
| SpaceX, Q3 10-Q: "Customer B", 34.5% of revenue, new in 2026; cloud contracts of about three years, cancellable on 90 days' notice | SpaceXAI compute from May 2026 into 2029, cancellable on 90 days' notice once early 2027 passes | Fits; circumstantial |
| Amazon, Q2 10-Q: Anthropic notes at $97.9 billion fair value | The same notes at $108.6 billion | $10.7 billion apart |
Alphabet: the $40 billion "private company"
Alphabet's 10-Q for January to March 2026 lists, under other information: "In March 2026, we committed to a $40.0 billion investment in a private company consisting of a $10.0 billion capital commitment and $30.0 billion of future capital funding contingent upon the achievement of specified operational and financial milestones." Its 10-Q for April to June shows the balance falling to "$20.0 billion of future capital funding commitments with a private company contingent upon the achievement of specified operational and financial milestones through 2030, which is accounted for as an equity derivative."
Anthropic's S-1 describes one agreement that fits every term.
| Term | Alphabet's filings, "a private company" | Anthropic's S-1, Google 2026 note purchase agreement |
|---|---|---|
| Signed | March 2026 | March 31, 2026 |
| Upfront money | $10.0 billion capital commitment | 38.6 million Series G-2 shares at $259.1364, about $10.0 billion |
| Contingent money | $30.0 billion | up to $30.0 billion of notes or non-voting stock |
| Conditions | operational and financial milestones | conditions under compute agreements and revenue targets |
| End date | through 2030 | requests through December 31, 2030 |
| After the second quarter | $20.0 billion left | $20.0 billion left after Google's $10.0 billion Series H purchase in May |
Alphabet never uses the name in either filing, although it confirmed the investment to the press in April, when Bloomberg reported it. On its calls it has named Anthropic three times, the last in October 2025.
“We are investing in TPU capacity to meet the tremendous demand we are seeing from customers and partners, and we are excited that Anthropic recently shared plans to access up to 1 million TPUs.”
Sundar Pichai, chief executive, Alphabet, earnings call, 29 October 2025
What Alphabet carries. At June 30, Alphabet held $124.3 billion of private stakes under the measurement alternative, which it says "primarily consist of our investment in a private company". Their cost rose $19.2 billion in the first half; the S-1 shows Google putting $20.0 billion into Anthropic stock in the same months. The S-1 leaves blank how many shares Google will hold. The series it ties to Google come to 111 million shares before the 10-for-1 split, worth about $65 billion at the Series H price of $589.01. By our arithmetic from the S-1's share count (846,840,960 shares are 5% of the fully diluted total), Series H valued all fully diluted shares at about $1.0 trillion, so a stake carried at $124.3 billion would be about 12%, under the 14.99% cap in Google's agreement. Alphabet's quarterly gain, $77.4 billion in April to June, can't be divided this way: Alphabet attributes its equity gains to "SpaceX and a private company" together.
The same Q1 10-Q says Google Cloud signed "a limited number of agreements to supply multiple gigawatts of TPU hardware" for customers' on-premises infrastructure, with most of the revenue in 2027, and agreed to credit backstops for third-party data centers. The S-1's TPU capacity arrives through Broadcom leases, run "in dedicated data center facilities operated by others on our behalf", starting in 2026 and expanding in 2027. The two descriptions are consistent, but neither filing links them, so we leave that one open.
Broadcom: the $42 billion notes and the $29 billion backstop
The S-1 describes five-year master equipment leases with Broadcom for TPU-based hardware, $161.2 billion of rent excluding interest, of which the 2026 lease is about $125.2 billion. To help pay that rent, Anthropic may issue Broadcom up to $42.0 billion of convertible notes, "solely to finance quarterly rent obligations under the 2026 Lease Arrangement", and Broadcom may assign the agreement to "a designated financial partner".
Broadcom's 10-Q for the quarter to August 2 has the mirror image: "In connection with lease agreements that enable access to compute capacity, our customer may, under certain circumstances and if needed, issue to us convertible promissory notes up to an aggregate principal amount of $42 billion," to be used "solely for the customer's obligations under the lease agreements". No notes had been issued by August 2, and the S-1 says Anthropic doesn't expect to issue any before the IPO. Same amount, same purpose, same status.
The leases have a second party now. Broadcom's 10-Q filed on June 9 says that on June 8, 2026 it "arranged for Apollo ("investor partner") to take on certain agreements to purchase AI racks based on custom AI accelerators designed by us and the related lease agreements with a customer", and that Broadcom backstops "the customer's lease obligations over 5-year terms", with "a maximum exposure of $29 billion". The August 10-Q calls this the first $35 billion tranche of its AI XPV platform, for more than 1 gigawatt of compute "for our customer", and says the backstop covers the gap between 85% of what the customer still owes and what the racks would sell for. By our arithmetic, 85% of $35 billion is $29.75 billion, in line with the $29 billion cap. Press reports have tied this arrangement to Anthropic since June, but Broadcom's filings say only "a customer". The S-1 records the same quarter's event in one sentence: Broadcom "assigned a portion of its rights under one of the master equipment leases to another third party." It names neither Apollo nor the backstop.
The dates on the calls are worth setting side by side. On the June 3 call, a Barclays analyst described the latest Anthropic deal as backstopped by Broadcom chips. Hock Tan answered that the description needed correcting: Broadcom was the one providing the chips and the compute capacity. Five days later, Broadcom moved the purchase agreements and leases to Apollo and signed the $29 billion backstop. On the September 2 call, the chief financial officer tied the June tranche to Anthropic's first gigawatt. Asked whether a $29 billion exposure was the order of magnitude for each of the Anthropic and OpenAI gigawatts to come, the CFO said there was nothing new to announce on backstops and the figures already given remained true.
Broadcom's backlog moved in the quarter that contains the March 31 date of the master lease filed with the S-1. Its firmly committed remaining performance obligations went from $45.0 billion to $164.6 billion in the quarter ended May 3, including "a long-term contract for custom AI accelerators entered in the fiscal quarter ended May 3, 2026", customer not named.
The two companies book the same racks differently. Broadcom counts a contract to sell custom accelerators; Anthropic counts finance leases. Broadcom's description of the Apollo deal shows the structure in between: an investor takes on the agreements to buy the racks and the related leases to the customer. Broadcom was open about the customer on its calls before any of this.
“As you are aware, last quarter, Q3 2025, we received a $10 billion order to sell the latest TPU ironwood racks to Anthropic. This was our fourth customer that we mentioned. In this quarter Q4, we received an additional $11 billion order from this same customer for delivery in late 2026.”
Hock Tan, president and chief executive, Broadcom, earnings call, 11 December 2025
SpaceX: who is Customer B?
SpaceX's amended S-1 from June 2026 named Anthropic as a cloud customer: a May 3, 2026 agreement for compute on about 325,000 Nvidia GPUs at its Colossus data centers, with a monthly fee through May 2029. Its 10-Q for July to September names no cloud customer, but its concentration note has a new one.
| SpaceX's Q3 10-Q | Anthropic's S-1 |
|---|---|
| "Customer B": 34.5% of Q3 revenue and 24.2% of nine-month revenue, not a 10% customer in 2025 | SpaceXAI agreements signed from May 2026 |
| Customer B's revenue sits in the segment that sells cloud services | compute "powered by NVIDIA GPUs" from SpaceXAI |
| cloud contracts: fixed monthly fee, "typically three years and terminable by either party upon 90 days' notice" | terms "extending into 2029"; after early 2027 "each agreement may be cancelled by either party upon 90 days' advance written notice" |
| one customer held 27.7% of receivables at September 30 | not disclosed |
The sizes fit as well. By our arithmetic, Customer B paid about $5.0 billion in the third quarter (34.5% of $14.6 billion), about $1.7 billion a month, and about $1.5 billion before July. Anthropic expects to pay about $3.1 billion a month once all capacity arrives in December 2026, with lower fees while capacity ramps; $120.5 billion is about 39 months of full-capacity fees, consistent with terms running into 2029. The match is circumstantial, and another tenant of SpaceX's data centers is the alternative. The terms also explain a gap: SpaceX reports $63.0 billion of total backlog and counts a contract only once there is an enforceable agreement, so the years after the cancellation window opens shouldn't be in it.
Amazon: the same securities on two balance sheets
Amazon is the partner that names Anthropic throughout, which makes it the one place where both sides of the same securities can be compared line by line. At June 30, every convertible note Anthropic had outstanding was held by Amazon: $6.2 billion of principal, convertible into 1.84 billion Class N shares.
Anthropic carries the notes at $108.6 billion, about $58.99 per share they convert into, essentially the Series H price of $58.90 after the split. Amazon's 10-Q puts them at $97.9 billion, about 10% lower, using its own estimates of the notes' rights and the timing of a liquidity event. Six months earlier the order was reversed: Amazon's $45.8 billion was above Anthropic's $41.7 billion. The issuer's mark has risen faster than the holder's.
That mark is what drives Anthropic's loss. The S-1's fair-value table rolls the notes from $41,677 million to $108,566 million: $5,499 million converted into preferred stock, and a $72,388 million change in fair value. That change is the full $72.4 billion charge in Anthropic's income statement, 90% of its $80.7 billion first-half net loss. Amazon books most of its side of the notes outside net income: their unrealized gain in other comprehensive income rose from $39.5 billion to $92.0 billion, and $4.5 billion moved into income when notes converted.
Amazon's net-income gains come from its preferred stock, and the S-1's share table lets us test them. Amazon's notes converted into 95.3 million Series E-2, 20.7 million Series F-2 and 20.6 million Series G-3 shares before April, and Amazon bought 19.3 million Series G-2 shares at $259.14 in the second quarter. If those 155.9 million shares were carried at the Series G price and marked to the Series H price with no discount, the second-quarter gain would be $51.4 billion. Amazon reported upward adjustments of $50.5 billion for the quarter and $62.8 billion for the half, within 2% of that test. Amazon carries its preferred at $92.5 billion; across the 164.4 million shares the S-1 attributes to it, including $5.0 billion of Series H, that is $562.70 a share, 4.5% below the Series H price.
Two smaller points reconcile too. Amazon describes a $20.0 billion facility that its $5.0 billion Series H purchase cut to $15.0 billion; the S-1's notes say the same, while its MD&A table lists $15.0 billion as the "original" amount (and Google's as $20.0 billion, against $30.0 billion in the notes). And Amazon's $15.9 billion of discrete tax expense on these adjustments is about a quarter of its $62.8 billion first-half gain. In all, Amazon's balance sheet carries $190.4 billion of Anthropic securities, about 19% of the $1.0 trillion Series H value by our arithmetic.
The Series G-2 price in a Series H quarter
Google agreed in March, and Amazon in April, to buy a combined 57.9 million Series G-2 shares at $259.14, the price of the Series G round in January and February. Both purchases closed in the second quarter, the same quarter Series H sold at $589.01 a share in May and June. The S-1's fair-value table shows the cost to Anthropic: the value of those purchase agreements fell by $11.75 billion before they settled, a loss inside the $8.76 billion of net other expense in the first half. The same shares sit in the buyers' upward adjustments.
The first half of 2026, from both sides
| Six months to June 30, 2026 | Amount | Where it is booked |
|---|---|---|
| Anthropic: rise in fair value of its convertible notes, all held by Amazon at June 30 | −$72.4 billion | net income |
| Anthropic: loss on the Google and Amazon Series G-2 purchase agreements | −$11.75 billion | net income, other expense |
| Anthropic: operating loss | −$0.7 billion | net income |
| Amazon: upward adjustments on Anthropic preferred stock | +$62.8 billion | net income |
| Amazon: gains moved to income when notes converted | +$4.5 billion | net income |
| Amazon: rise in unrealized gain on the notes | +$52.5 billion | other comprehensive income |
| Alphabet: gains on non-marketable stakes, "SpaceX and a private company" | +$113.6 billion | net income, not split by company |
| Microsoft: gain on its Anthropic investment, April to June | +$3.2 billion | net income |
| Salesforce: gain on its Anthropic investment, February to July | +$3.0 billion | net income |
None of these lines is cash. Anthropic's operating loss for the half was $693 million on $16.3 billion of revenue. Salesforce's 10-Q makes a useful outside check: it carried its Anthropic stake at $5.1 billion on July 31 after a $2.7 billion gain in May to July, 53% of the carrying value. Marking a stake from the Series G price to the Series H price adds 56% of the new value, so the two are close.
Microsoft, Nvidia and AMD
Microsoft's commitment from Anthropic is at least $44.9 billion from November 2026 to May 2033, signed in November 2025 and amended in February and October 2026. Microsoft counted it in bookings on its January 28 call, and its July results release lists "a $3.2 billion gain from our investment in Anthropic"; its annual report doesn't mention Anthropic.
“Commercial bookings increased 230% and 228% in constant currency, driven by the previously announced large Azure commitment from OpenAI that reflects multi-year demand needs, as well as the previously announced Anthropic commitment from November, and healthy growth across our core annuity sales motions.”
Amy Hood, chief financial officer, Microsoft, earnings call, 28 January 2026
Nvidia's 10-Q of November 2025 disclosed "an agreement, subject to certain closing conditions, to invest up to $10 billion in Anthropic". Its annual report and two 10-Qs since don't mention Anthropic.
“This quarter, we announced a partnership with Anthropic and a $10 billion investment in their company. Anthropic will train and inference on Grace Blackwell and [Vera Rubin] systems.”
Jensen Huang, chief executive, Nvidia, earnings call, 25 February 2026
AMD's results release of August 4 announced up to 2 gigawatts of MI450 GPUs in Helios racks for Anthropic. The S-1 adds that AMD committed to buy up to $5.0 billion of Anthropic's Class N stock as deliveries are met, with the first milestone expected in 2027. AMD's 10-Q for the quarter to June 27, filed August 5, doesn't mention it; the agreement was signed in July.
What the S-1 leaves blank or unnamed
- Related parties. The S-1 defines related persons by holdings of voting stock. Amazon and Google hold non-voting stock, so the related-party financing tables list only Spark Capital and a director's company, not the two partners with the largest stakes and the largest contracts.
- Holdings. The number of Class N shares Amazon and Google will hold after the offering is left blank.
- Other buyers. Besides Google's and Amazon's shares, 26.0 million non-voting Series G-2 shares were sold in the first quarter, about $6.7 billion. The S-1 doesn't say to whom, and doesn't name Microsoft or Nvidia as investors.
- Commitments. Fixed or minimum purchase commitments were $265.6 billion at June 30. Agreements signed or amended after June 30 add about $245 billion of minimum payments, some of which may overlap with amended earlier ones. The September 30 table, the run-rate revenue and the offering terms are still blank.
The compute agreements in the S-1
| Supplier | What Anthropic agreed to | Amount | Period | Can Anthropic walk away? |
|---|---|---|---|---|
| Broadcom | Five-year master equipment leases for TPU-based hardware | $161.2 billion of rent, excluding interest | five years from delivery | No, except on default |
| SpaceXAI | Compute on Nvidia GPUs, about $3.1 billion a month at full capacity | up to $120.5 billion | into 2029 | Yes, on 90 days' notice after initial periods ending January and March 2027 |
| Minimum spend, with a true-up payment | at least $114.5 billion | April 2026 to July 2033 | No, except on Google's uncured breach | |
| Amazon | Minimum spend, with a true-up payment | at least $110.0 billion | May 2026 to April 2036 | No, except on Amazon's uncured breach |
| Microsoft | Minimum spend | at least $44.9 billion | November 2026 to May 2033 | No, except on breach or for undelivered tranches |
| Nscale | Compute on Nvidia GPUs, fees as capacity is accepted | up to $44.6 billion | into 2033 | Only in limited cases; Nscale must use best efforts to finance the hardware |
| Lambda | Compute on Nvidia GPUs, fees as capacity is accepted | $41.3 billion | into 2034 | Either side can end the $34.9 billion August agreement if Lambda doesn't secure the facility lease in time |
| AMD | Helios rack-scale systems with MI450 GPUs | more than $20.0 billion expected | from 2027 | No fixed dollar amount in the contract |
These add up to about $657 billion, but they are different kinds of promise: minimums, ceilings and lease rent. Anthropic also estimates $125 billion to $150 billion of further TPU compute from providers including Google for 2028 to 2031. For scale, its revenue was $4.6 billion in 2025 and $16.3 billion in the first half of 2026, and compute and infrastructure cost 55% of that half's revenue.
Anthropic on other companies' calls, and its customers' silence
Anthropic has become a regular name on earnings calls well beyond its partners. We counted every call in our transcript library that uses the word.
From July to September 2026, 98 calls named it, 1.7% of the quarter's calls in our library, against 19 a year earlier; 234 companies have named it since 2023, 90 of them software companies.
The S-1 also features customer case studies, each with a "customer since" date. We checked the public companies among them against their own calls, counting only executives, not analysts.
| Customer in the S-1 | Customer since | Executives named Anthropic or Claude on a call? |
|---|---|---|
| Salesforce, SAP | 2023 | Yes, since 2023 |
| AIG, Verizon, Bristol Myers Squibb | 2023 | Yes, first in 2025 or 2026 |
| PayPal, Travelers, Accenture, Shopify | 2024 or 2025 | Yes, first in 2025 or 2026 |
| DoorDash | 2023 | Only in an analyst's question |
| Walmart, Eli Lilly, MercadoLibre, Rakuten | 2023 or 2024 | No |
Walmart's case study reports a 110% quarter-over-quarter rise in weekly users of its Sparky shopping agent, which Anthropic says it worked on with Walmart; Walmart has not named Anthropic or Claude on any call in our library.
What to watch
- The cloud results this week. Alphabet, Microsoft and Amazon report July to September between October 28 and 30. Watch whether Alphabet's funding commitment is still $20.0 billion and whether it names the company now that the S-1 is public.
- Broadcom's annual report. Its fiscal year ends in early November; the backstop exposure grows as racks are deployed, and the September call pointed to 5 more gigawatts for Anthropic in 2027.
- SpaceX's Customer B. If it is Anthropic, its share of SpaceX's revenue should rise toward $3.1 billion a month as capacity completes in December.
- The amended S-1. It should fill in Amazon's and Google's holdings, the September 30 commitments and the offering terms.
Method
We read Anthropic's S-1 (SEC accession 0001628280-26-067168, filed October 26, 2026) in full, including Notes 9 and 16 on convertible notes and preferred stock, the Level 3 fair-value table, the commitments and subsequent-events notes, the related-party section and the exhibit list.
For each counterparty we read the filings in our database for the same period: Alphabet's 10-Qs for January to March and April to June 2026; Amazon's 10-Q for April to June; Broadcom's 10-Qs filed June 9 and September 10 and its June and September calls; SpaceX's amended S-1 of June and its 10-Q for July to September; Microsoft's annual report and July results release; Nvidia's 10-Qs and annual report since November 2025; AMD's results release and 10-Q filed in August; and Salesforce's 10-Q for May to July. We searched each for "Anthropic", for unnamed counterparties ("a private company", "a customer", "Customer B"), and for the amounts, dates and terms in the S-1, then compared them line by line.
Share counts are the S-1's, before the 10-for-1 split unless noted. The Amazon gain test assumes all of Amazon's pre-Series H shares were carried at the Series G price and marked to the Series H price with no discount. The $1.0 trillion value is our arithmetic: the S-1's fully diluted share count, from its 846,840,960-share 5% issuance, times the Series H price after the split. For the call count we searched every earnings call transcript in our library for the whole word "Anthropic" and counted each call once, keeping one copy where the library holds two transcripts of the same call.
Limitations
None of the Alphabet, Broadcom or SpaceX filings we compared names Anthropic. Alphabet's "private company" and Broadcom's "customer" match the S-1 on every term we could compare, and both deals were reported as Anthropic's in the press; SpaceX's "Customer B" is our inference from timing, contract terms and size, and another customer could fit. Fair values are each company's own estimates, made with different methods and dates. The S-1 is preliminary and leaves holdings, the September 30 commitments and the offering terms blank. Alphabet, Amazon and Microsoft report again within days, and those reports will update every figure here.
This is an analysis of public documents, not investment advice.