Anthropic at $2 trillion? What an IPO would actually change for two Baillie Gifford trusts

The spectacular number is $2 trillion. For shareholders in Baillie Gifford US Growth Trust and Scottish Mortgage, however, it is not yet the most useful one.

On 4 September 2026, the Financial Times reported that Anthropic was close to awarding the leading roles in its initial public offering to Morgan Stanley and Goldman Sachs. According to the newspaper, a public filing could come shortly, followed by an autumn listing at a discussed valuation of $2 trillion or more.

These are not Anthropic announcements. The mandates were reportedly not final. No public prospectus yet discloses the accounts, capital structure, dilution, rights attached to each share series, offer size or selling restrictions. The valuation must therefore be treated as a reported indication, not a transaction.

The signal nevertheless deserves an article. Anthropic is not a distant curiosity in the portfolios. At 31 July, it represented 6.6% of Baillie Gifford US Growth assets and 2.8% of Scottish Mortgage assets. Based on published totals, that is about £63 million in the first trust and £466 million in the second.

A possible IPO would not merely change the potential value of these positions. It would change their nature: pricing frequency, potential liquidity, volatility, financial disclosure, observable governance and the space occupied in each trust's private portfolio.

Thirty-second summary

The reported information. According to the Financial Times, Anthropic is close to choosing Morgan Stanley as lead-left bank and Goldman Sachs as stabilisation agent. A public filing could come shortly and an autumn listing is being considered. Decisions and timing are not final.

The holding-company exposure. At 31 July 2026, Anthropic represented 6.6% of Baillie Gifford US Growth assets, or about £63 million, and 2.8% of Scottish Mortgage assets, or about £466 million. In relative weight, the event matters more to US Growth. In absolute pounds, it matters much more to Scottish Mortgage.

The mechanism. A listing could provide a public price and, after any restrictions, a path to liquidity. It guarantees neither an increase in value, an immediate sale nor a narrowing of trust discounts.

The central unknown. Without a prospectus and details of the share classes held, a $2 trillion headline valuation cannot be translated into a precise gain in NAV per share.

Two trusts, two opposite sensitivities

The same Anthropic news does not pass through to the two vehicles in the same way.

Baillie Gifford US Growth is more sensitive in percentage terms. Its published total assets at 31 July were £960.16 million. At 6.6%, Anthropic is indicatively worth £63.4 million. It is the portfolio's fourth-largest holding, ahead of Amazon, and about 22% of the entire private-company sleeve.

Scottish Mortgage is more exposed in pounds. Its published total assets were £16.66 billion. At 2.8%, Anthropic is indicatively worth £466.5 million. The weight is less concentrated, but the amount is more than seven times US Growth's. Anthropic is about 12% of Scottish Mortgage's private-company sleeve.

This asymmetry matters to any reader of the trusts. The security most sensitive to a relative change in Anthropic's value is US Growth. The vehicle where a future sale could release the most capital in absolute terms is Scottish Mortgage.

Adding the two amounts, about £530 million, shows the scale of exposure managed by Baillie Gifford across these two trusts. It does not create a joint legal position. Each company has its own board, capital structure, NAV and discount.

What an IPO changes before it changes the price

A private company enters NAV through periodic valuation. The manager uses financing transactions, comparables, security rights and judgement. The number is essential, but not continuously observable.

A listed company instead produces a market price every session. That does not always make it fair. It makes it visible, frequent and contestable.

For both trusts, the first effect of a successful IPO could therefore be a reclassification from private to listed, initially at unchanged value. Mechanically and all else equal, US Growth's private sleeve would fall from 29.8% to about 23.2%, and Scottish Mortgage's from 23.0% to about 20.2%.

That move adds no NAV. It changes room to manoeuvre. US Growth may invest up to 50% of assets in private companies at the time of investment. Releasing 6.6 percentage points from the private sleeve, if Anthropic becomes listed, would restore meaningful capacity to fund new private companies without increasing overall private exposure.

At Scottish Mortgage the relative effect would be smaller, but converting roughly £466 million of private assets into a listed security would materially alter potential portfolio liquidity.

Listed does not mean saleable the next day

This is the most important distinction after rumour versus filing.

Existing shareholders in newly listed companies are often subject to lock-ups. Their duration, exceptions, secondary-sale possibilities and conversion rights depend on the prospectus and contracts. Until those documents are public, no liquidity date can be assigned to the two trusts.

The holding may therefore pass through three successive states:

A listing therefore changes the quality of information first, the frequency of valuation second, and effective liquidity only later.

Why $2 trillion cannot be applied by rule of three

On 1 September, Shaires Holdings said it had closed an indirect Anthropic exposure based on a $965 billion Series H valuation. The Financial Times now reports a discussed IPO valuation around $2 trillion.

The comparison naturally attracts attention: the second number is more than twice the first. Yet multiplying the £63 million and £466 million positions by that ratio would manufacture precision.

At least six variables are missing:

1. The security held. Portfolio disclosures refer to preferred shares, including F-1 and H-1 series. Their rights may differ from common shares sold to the public. 2. Price per share. An aggregate valuation is insufficient without a fully diluted share count and proposed offer price. 3. Dilution. A primary IPO creates new shares and raises capital. Existing investors' economic percentages may fall. 4. Conversion. Preferred shares may convert under terms that must be read. 5. Currency. Trust assets are published in sterling while the valuation indication is in dollars. 6. Marking date. Boards and the manager may reflect events under their fair-value policy before, at or after listing.

Editorial discipline here means resisting the most beautiful number in the story. A contemplated valuation is the start of an investigation, not certified NAV.

The prospectus would matter more than the first trade

The first market price will be spectacular. For a reader of the trusts, the prospectus will be more useful.

It could answer questions the factsheets cannot: audited revenue, customer concentration, compute spending, capacity-purchase commitments, cash burn, share-based compensation, cloud-provider relationships, litigation, risk factors, board composition and the exact capital structure.

These disclosures would finally connect Anthropic's operating economics to the value carried by the trusts. Our 4 September article on Fable 5.1 usage cost already showed today's limit: Anthropic publishes cost reductions for selected workloads but not how they pass through to revenue, gross margin or cash consumption. A prospectus could turn that chain of assumptions into testable data.

For the trusts, the great break created by an IPO is not merely that the market gives Anthropic a price. It is that Anthropic must provide enough information for that price to be debated.

Governance would not suddenly become ordinary

Anthropic is a public benefit corporation. In 2023, it described its Long-Term Benefit Trust, an independent body designed to select and remove a growing share of its board, ultimately a majority. According to Anthropic, the Class T shares created for the trust do not carry ordinary shareholders' financial interest.

The Financial Times reports that the body now appoints four of seven directors and that Anthropic intends to preserve its role after listing. If confirmed in the prospectus, public shareholders will buy into a company where the majority of directors does not depend solely on conventional economic voting power.

For Scottish Mortgage and US Growth, this is neither automatically positive nor automatically negative. It is a governance condition that belongs in the risk analysis. It may protect a long-term mission from quarterly pressure. It may also create a gap between economic power and appointment power, particularly when safety, deployment and capital decisions conflict.

The prospectus will need to explain composition, rights, removal procedures, potential conflicts and interaction with shareholders. Once again, listing does not erase the private company's singularity. It makes that singularity accountable to the market.

The discount paradox

At 31 July, Baillie Gifford US Growth shares traded at an 8.3% discount to NAV, and Scottish Mortgage at an 8.0% discount.

A large private holding can contribute to uncertainty around NAV. An Anthropic listing could therefore remove one source of doubt: price would be public, financial disclosure richer and an eventual exit conceivable.

But it could also add volatility. A public price at 4pm is less smooth than a periodic private mark. If Anthropic falls after listing, trust NAV will reflect the move faster. If it rises, the same applies, subject to the treatment of locked securities and class rights.

The link between IPO and discount is therefore not one-way.

For trust shareholders, the IPO may make NAV more legible. It does not promise that the share price will converge with NAV.

What would move the article from conditional to calculable

The 4 September signal is strong enough to prepare readers. It is not complete enough to announce value creation.

Three documents or events will advance the evidence:

1. The public filing. It will provide fully diluted capital, accounts, risk factors, governance rights and proposed terms. 2. Trust updates. They will reveal the value adopted, the classes held, any conversion and the intended holding policy. 3. The end of restrictions. It will turn a listed but locked security into a genuine allocation option for each board.

Until then, the conclusion must remain narrower than the spectacular headline.

Anthropic may move from private markets to the public market. For Baillie Gifford US Growth, that would affect one of the portfolio's largest concentrations and more than one fifth of the private sleeve. For Scottish Mortgage, it would involve almost half a billion pounds and a meaningful portion of future liquidity.

The $2 trillion valuation may tell us what the market is prepared to pay. The prospectus will tell us what the two trusts actually own. And the lock-up will tell us when that value can become a capital choice.