CBA sits on a $2.8 billion Anthropic windfall it probably can't touch

Commonwealth Bank stands to book a paper gain of roughly $2.8 billion on its stake in Anthropic — but the bank likely can't sell a single share when the AI giant lists, according to MST Marquee analyst Brian Johnson.

CBA made the investment in March last year under CEO Matt Comyn. The goal wasn't a quick flip: Australia's largest bank wanted alignment with Anthropic and access to its most advanced AI models, technology and engineering expertise. A CBA spokesman declined to comment on Tuesday about the bank's plans for the holding.

Johnson puts the odds of a clean exit at close to zero. "It's reasonable to expect CommBank can't just sell its shares into the IPO. I am suspecting they will be locked out of selling," he said. He also cautioned that key details of the mooted Anthropic IPO remain unknown, including shares issued to staff and any dilution of CBA's stake via a convertible note.

How the $2.8 billion maths works

The number rests on one scenario. If Anthropic raises $US100 billion at a market valuation of $US1.6 trillion to $US2 trillion, CBA's stake would be worth about $US2.07 billion — roughly $2.8 billion in Australian dollars. In plain terms, the bank's initial cheque has multiplied several times over in under two years, at least on paper.

Paper is the operative word. Until the IPO pricing lands and lockup terms are disclosed, the gain stays theoretical.

What does this change for CBA shareholders?

Probably nothing immediate. CLSA banking analyst Ed Henning points to the bank's own history: "The previous [CBA] playbook from Klarna shows there is a possibility that they could sell down moderately [at IPO], but they are not in desperate need of capital, so they could continue to hold on."

There's precedent for a partial exit. When Swedish buy-now-pay-later firm Klarna listed last year, CBA sold part of its stake in the IPO and netted about $100 million. That's pocket change against a potential $2.8 billion — but it shows the bank's template: trim, don't dump.

Jarden analyst Matt Wilson framed the signal risk bluntly. "They may take some profit if they can, if they are allowed to," he said. "If they sold [the entire stake], it would be a very bearish signal."

Wilson also noted that Comyn is an "AI enthusiast" — which cuts toward holding. The Anthropic relationship, as Johnson put it, "probably goes beyond the notional investment gain and just having an equity stake." For a bank betting its future on AI capability, the strategic access may be worth more than the windfall.

The listing lands in a shakier AI market

Timing is the wrinkle. Investor confidence in AI growth — and in the sector's ability to fund capital-intensive rollouts — has wavered over the past three weeks. Investors baulked at the proposed $44 billion valuation for float candidate and neocloud Firmus Technologies, and they've openly questioned the heavy debt load at AI cloud platform CoreWeave.

Anthropic would be listing into that breeze. For CBA, a softer AI sentiment cuts both ways: a lower float valuation shrinks the paper gain, but a stake held long keeps the strategic access intact regardless of the IPO price.

The banks aren't just watching

Australian banks are racing to keep pace with AI model development. CBA will host an Accelerate AI customer event in mid-November to assess how businesses are translating AI ambition into measurable outcomes. At a similar event earlier this year, Comyn interviewed OpenAI co-founder Sam Altman by video.

CBA also holds a strategic relationship with OpenAI, which the pair have used to jointly launch an AI, cybersecurity and digital initiative for small businesses. National Australia Bank has scheduled its own AI investor event for November 30.

Expect clarity only when Anthropic files its IPO terms. Until then, CBA's $2.8 billion remains a locked-up marker of how far a bank's AI bet has run — and how little of it the bank can currently spend.