(Bloomberg) — Immediately after Anthropic expanded a ban on popular ways to buy its shares, investor chat rooms around the world were ablaze. “Are we fucked?” one person wrote in a WhatsApp chat for family offices with several hundred members. Similar questions echoed further on X, Reddit and Chinese social media as investors worried whether their shares in the artificial intelligence developer, one of the most coveted private companies, had suddenly become worthless. Days later, there is little clarity. Anthropic PBC took the unusual step of publishing a stern warning about unauthorized sales on its website last week, naming eight firms whose bids would be voided. It also expressly prohibited investors from buying shares through special purpose vehicles, a common vehicle for raising financing. Both Antropik and rival OpenAI have long warned against unauthorized transactions; Detailed information that was overlooked by eager buyers until last week, when the Claude maker cleared up any uncertainty. Following the update, public funds touting exposure fell and private brokers were stunned. Sim Desai, founder of Hiive, one of the secondary trading platforms Anthropic called out, said his company only facilitates deals with Anthropic’s approval. Sohail Prasad, whose closed-end fund lost nearly 25% of its share value in the intervening days, was adamant about X that his fund’s Anthropic holdings were valid.
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“Anthropic bombed the market,” said Idan Miller, who runs Unicorns Exchange, another platform Anthropic named. “Unfortunately, we were involved in this situation in a really bad and unfair way.” Representatives for Anthropic declined to comment. An OpenAI representative said the company is taking action against unauthorized platforms offering its shares. Over the past two years, a niche private market sector has turned into a multibillion-dollar investment frenzy for shares of Anthropic, OpenAI and SpaceX ahead of their expected blockbuster IPOs. These firms, at the forefront of the tech boom, have generated enormous paper profits for major venture firms and institutional funds. Some insiders tried to cash in on their risks as family offices, retail investors and wealthy individuals clamored to get in wherever they could, fueling a booming shadow stock market. Anthropic is in talks for additional financing at a valuation of over $900 billion, Bloomberg News reported, and secondary traders are marketing its shares at even higher prices. The crackdown “signals the beginning of a reckoning on our modern private markets,” wrote Anat Alon-Beck, a law professor at Case Western Reserve University who specializes in corporate governance in pre-IPO companies. “Questions arise, such as who really owns what? Who bears the risk when shadow ownership structures collapse? Should private trillion-dollar companies continue to operate outside the disclosure framework that governs other large corporations?”
Miller said his Tel Aviv-based firm serves only as a broker, connecting sellers of Anthropic shares with willing buyers and always obtaining the company’s approval. Other companies on Anthropic’s list made similar arguments.
Forge Global, a well-known secondary platform, said it was working with Anthropic to remove its name from the list of unauthorized sellers; As of Monday, Forge is still there. Brokerage firm Charles Schwab Corp. acquired Forge for $660 million last November.
Both OpenAI and Anthropic have greenlit some secondary transactions, primarily through tender offers in which employees and investors can sell their shares. Anthropic also approved an $884 million share transfer from FTX, which was one of the first investors following the crypto exchange’s bankruptcy.
A number of companies offer platforms for these secondary transactions, which are increasingly common for fast-growing startups. As secondary sales have grown, so have SPVs, which are now a standard piece of financing for many pre-IPO companies and a path for smaller investors to acquire. Menlo Ventures, one of the early Anthropic backers, put together its own $500 million check in an earlier round of financing using an SPV, according to an SEC filing first reported by Business Insider. But as funding rounds grew larger, SPVs became complex and murky, with little clarity for the buyer and reduced transparency for the startup. “Anthropic has and should have the right to control the cap table and shareholder base,” said Matt Murphy, the Menlo partner who led the company’s investment. He said his firm does not use SPVs of the type banned by Anthropic. “Unauthorized SPVs are not in the interest of the company and can often be downright dubious,” he said. “Buyer beware.” In a recent email conversation reviewed by Bloomberg News, the “Family Office Network” broker in Dubai offered potential buyers a block of Anthropic shares at a valuation of $1.2 trillion through an SPV in exchange for a 10% cut. This was a “layered” vehicle; This means that the vehicle sold by the broker is invested in another SPV that claims to own the shares.
“You need to transfer money by Monday,” the message said. Multilayer SPVs are not uncommon, accounting for $227 million of the $3.5 billion in secondary market transactions in 2025, according to Caplight, a data provider and platform. Ludovic Phalippou, professor of financial economics at Oxford University Said Business School, said banks and blue-chip financial firms are flocking to this market as wealthy customers demand access to hot private companies. But these are “opaque, fragmented and can sometimes involve claims to shares rather than actual transferable shares,” he said. He added that the proliferation of SPVs is a bad outlook for companies and could create legal problems in the future. Limiting the gray market also allows Anthropic to rein in competing narratives about how much it’s worth as the company moves toward an anticipated blockbuster IPO. Secondary trading in its current form means the company could go public at a valuation north of $1 trillion — Walmart Inc. or close to Tesla Inc.’s market cap. “Immediately audit your anthropic exposure,” an executive of the SPVs wrote to a family office on May 12, according to a copy of the message viewed by Bloomberg News. “If Anthropic is doing this today, it’s reasonable to expect other high-value private companies preparing for IPOs or large financing rounds to follow suit.” The email also told investors to call their legal counsel. Anthropic, OpenAI and Anduril define share transfers made without their knowledge as “void”. “Anthropic said the SPVs were void, non-cancellable, meaning they were never valid to begin with,” said Alon Kapen, partner at law firm Farrell Fritz. “This essentially means that investors in SPVs have no claim against Anthropic.” Many SPV investors bought interest “out of an empty box,” he added. Following Anthropic’s update, Hiive’s Desai wrote of Two closed-end funds that disclosed holdings in Anthropic and OpenAI through SPVs, Fundrise Innovation Fund LLC and Destiny Tech100 Inc., are down about 29% and 33% since the Anthropic update.Fundrise described its shares as a “Everyday Americans” stock in its March presentation. [getting] “We have been deprived of a once-in-a-generation wealth event.” The document states that the fund’s largest holding, with 20.7% of its portfolio, is in Anthropic. In a separate application, it was stated that these shares were purchased through an SPV. A Fundrise representative did not respond to a request for comment. Destiny Tech100 CEO Prasad said in his statement about X that the company is “confident in the investment”. Jared Carmel, founder of secondaries specialist Manhattan Venture Partners, which took a stake in Anthropic after the FTX fire sale, received a barrage of questions last week from investors who purchased SPVs outside his own fund. “When people realize what they really do or don’t have, they will be fully exposed,” he said.
London-based family office consultant Justin Taylor said the mad rush to buy Anthropic, OpenAI and SpaceX meant investors were skimping on the due diligence process and missing out on detailed information about terms. “In the words of Tolkien,” he said, “‘All that is gold does not glitter.’” Kapen, Farrell Fritz’s attorney, expects the matters to eventually be resolved in court. Meanwhile, many potential investors are speculating. In the family office chat, one person responded briefly to whether Anthropic SPV owners were being harassed: “Ask Claude.”
–With help from Bailey Lipschultz and Henry Ren.
(Updates with more secondary market-related content in paragraph 23.)
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